Page 2 of 62

Problem Formulation for the Environmental Fate, Ecological 

Risk, Endangered Species, and Drinking Water Exposure 

Assessments in Support of the Registration Review of 

Chloropicrin

TABLE OF CONTENTS

1. EXECUTIVE SUMMARY .........................................................................................3

2. INTRODUCTION .......................................................................................................4

3. USE CHARACTERIZATION.....................................................................................5

3.1. Use Sites............................................................................................................... 5

3.2. Antimicrobial Uses............................................................................................... 6

3.3. Typical Agricultural Methods.............................................................................. 7

4. CONCLUSIONS FROM PREVIOUS ASSESSMENTS............................................8

4.1. Ecological Risk Assessments............................................................................... 8

4.2. Drinking Water Exposure Assessments............................................................... 8

4.3. Clean Water Act Programs................................................................................... 8

5. ENVIRONMENTAL FATE AND TRANSPORT......................................................9

5.1. Fate and Transport in Soil and Water................................................................. 11

5.2. Movement in Wood............................................................................................ 12

5.3. Fate and Transport in Air ................................................................................... 12

5.4. Transformation Products.................................................................................... 14

6. RECEPTORS.............................................................................................................15

6.1. Effects to Aquatic Organisms ............................................................................ 16

6.2. Effects to Terrestrial Organisms ........................................................................ 17

6.3. Ecological Incidents........................................................................................... 19

7. EXPOSURE PATHWAYS OF CONCERN .............................................................20

7.1. Agricultural Uses................................................................................................ 20

7.2. Antimicrobial Uses............................................................................................. 21

8. ANALYSIS PLAN ....................................................................................................21

8.1. Stressors of Concern........................................................................................... 21

8.2. Measures of Exposure ........................................................................................ 22

8.3. Measures of Effect ............................................................................................. 25

8.4. Antimicrobial Uses............................................................................................. 25

9. Endangered Species Assessments..............................................................................26

10. Endocrine Disruptor Screening Program...................................................................27

11. PRELIMINARY IDENTIFICATION OF DATA GAPS..........................................27

11.1. Environmental Fate......................................................................................... 27

11.2. Effects............................................................................................................. 28

12. REFERENCES ..........................................................................................................34

Appendix A. SIP and STIR Results...................................................................................40

Appendix B. Field Volatility Study Summaries...............................................................42
Page 3 of 62

1. EXECUTIVE SUMMARY

The Environmental Fate and Effects Division (EFED) and the Antimicrobials Division 

(AD) have completed the preliminary problem formulation for the ecological risk, 

environmental fate, endangered species, and drinking water assessments to be conducted 

as part of the registration review of chloropicrin (PC 081501; CAS Registry Number 76-

06-2). The problem formulation describes the methods planned for the completion of 

drinking water and ecological risk assessments and provides an overview of the 

environmental fate, ecological effects, and potential risks associated with the use of 

chloropicrin. The problem formulation also addresses uncertainties unique to risk 

assessment of chloropicrin. This document identifies additional studies that would be 

beneficial to the conduct of an ecological risk assessment for the conventional uses. No 

further assessment is planned for the antimicrobial uses as exposure from these uses is 

expected to be negligible. Major findings include:

Environmental fate and transport data gaps:

• 835.4300 – Aerobic aquatic metabolism

• 850.6100 – ECM and ILV studies in air and water

Ecotoxicology data gaps:

• Aquatic

o 850.4500 – Aquatic non-vascular plant studies

• Terrestrial

o 850.4100 – Seedling emergence study

o 850.4150 – Vegetative vigor vapor exposure study with additional 

species*

o Non-guideline – Avian acute inhalation study with bobwhite quail*

o Non-guideline – Acute honey bee vapor exposure study*

*A protocol should be submitted to the Agency for approval prior to initiating the study.

Major uncertainties:

The largest uncertainty in quantifying aquatic exposure in this assessment will be the 

impact of tarps, especially bedded tarps, on the likelihood of chloropicrin to run off the 

field and the concentration of chloropicrin in the runoff. Another uncertainty is the 

impact of rainfall occurring close to the time of application on the runoff and 

volatilization rates of chloropicrin in the environment.

For terrestrial exposure, estimated environmental concentrations (EECs) in air will 

conservatively assume that birds and mammals are not transient and are exposed to 

emissions of chloropicrin downwind from the treated field. Such an assumption is 

perhaps more representative for plants since they are not transient. One uncertainty for 

air EECs is the propensity for large exposures to occur on timescales less than one hour. 

Such conditions are often associated with temperature inversions when light and variable 

wind speeds and highly stagnant air with limited mixing can occur. Therefore, peak air 
Page 4 of 62

concentrations may be underestimated by modeling. However, it is not expected that 

these conditions would significantly impact the expected frequency of exposure events 

since these conditions may only occur within a few hours of some days after fumigant 

applications. 

In addition, current labels contain specific language restricting applications during 

temperature inversions citing a number of criteria indicating the presence or forecasted 

temperature inversion. Another uncertainty includes the consideration of field size for 

the quantification of air EECs. Air EECs will be based on emissions occurring from a 

maximum field size of 80 acres. Eighty acres is considered to be the upper-bound field 

size for the maximum area that is typically treated in one day. 

2. INTRODUCTION

Chloropicrin is a broad spectrum fumigant used in pre-plant fumigations and 

antimicrobial wood treatments. Chloropicrin’s specific mode of action is not understood, 

but it is a strong irritant that is very toxic to all biological systems, affecting body 

surfaces and interfering with the respiratory system and the cellular transport of oxygen 

(USEPA, 2007c). Chloropicrin is commonly formulated along or with methyl bromide or 

telone (1,3-dichloropropene) as an emulsifiable concentrate, soluble concentrate/liquid, 

ready-to-use liquid, or pressurized gas when applied as a pre-plant soil fumigation 

(USEPA, 2013).

Chloropicrin is volatile and is expected to reside mainly in the gas phase following 

application. For soil uses, it is expected that post-application soil sealing methods (e.g., 

tarps, water, or soil) will be the largest factor determining off-site movement of dissolved 

chloropicrin vapors via runoff to water bodies or chloropicrin vapors to air. Given its 

high water solubility, leaching of dissolved chloropicrin vapors to ground water is also 

possible in well-draining sandy soils in areas where the water table is shallow. Once in 

water, chloropicrin aquatic exposure will be mediated by volatilization.

EFED and AD evaluated the most recent ecological risk assessments for chloropicrin in 

association with the most recent toxicity, exposure, and usage information to determine if 

sufficient data are available and if further updates are needed to support registration 

review. Recent ecological risk assessments include a 2009 amended reregistration 

eligibility decision (RED) assessment (USEPA, 2009a) and a 2007 California red legged 

frog assessment (USEPA, 2007c). 

In addition, EFED and AD considered the latest Agency science policies and risk 

assessment methodologies. 
Page 5 of 62

3. USE CHARACTERIZATION

Chloropicrin is a broad spectrum fumigant with fungicidal, herbicidal, insecticidal, 

nematicidal, and bacteriocide/bacteriostat properties that is often combined with other 

fumigants to broaden the pest control spectrum. Chloropicrin was initially registered in 

the U.S. in 1975 for use on agricultural crops/soils, greenhouse soils, and ornamentals, as 

wood protection treatments, and for enclosed space fumigation. However, under the 

Reregistration Eligibility Decision (RED) for chloropicrin issued in 2008 and amended in 

2009, structural greenhouse and/or enclosed space fumigation of commodities or other 

uses were canceled and additional restrictions were added for the pre-plant soil uses. At 

the time of reregistration, the maximum application rate supported for chloropicrin was 

350 lbs a.i./A, with 300 lbs a.i./A the maximum for drip irrigation (USEPA, 2008). All 

chloropicrin labels have been updated to reflect these application limits.

Chloropicrin is commonly formulated alone or with methyl bromide or telone (1,3-

dichloropropene) as an emulsifiable concentrate, soluble concentrate/liquid, liquid ready 

to use, or as pressurized gas and applied as a pre-plant soil fumigation and soil broadcast 

treatment. Chloropicrin is applied using tractor-mounted and other soil fumigation 

injection equipment, shanks, chisels, plowsoles, drip irrigation, hand operated soil 

injection equipment, shampoo machines, and encapsulated vials (USEPA, 2013). 

3.1. Use Sites

Chloropicrin is registered for use as an agricultural pre-plant soil fumigant for crops 

including beans, beets, bell peppers, caneberries, carrots, citrus, cole crops, cucumber, 

cucurbit vegetables such as melons, deciduous fruit trees, eggplant, field crops such as 

corn, soybeans, and sugar beets, fruits unspecified, ginger, grapes, hops, legume 

vegetables, lettuce, mint, onions, orchards, peanuts, pepper, pineapple, potatoes, radish, 

stone fruit, strawberry, sweet potatoes, tomatoes, tree nuts, yams, and other vegetables. 

Other registered non-food sites include Christmas tree plantations, conifers, forest 

nursery plantings (for transplant purposes), forest plantings (reforestation programs), golf 

course turf, nonagricultural uncultivated areas/soils, nursery stock, ornamental and/or 

shade trees, ornamental grasses, ornamental herbaceous plants, ornamental lawns and 

turf, ornamental nonflowering plants, ornamentals unspecified, ornamental woody shrubs 

and vines, potting soil/top soil, recreation area lawns, preplant soil, tobacco, and wood 

protection treatment to buildings/products outdoor, forest products (seasoned), and 

aquatic structures/items.

The Biological and Economic Analysis Division (BEAD) has generated a chemical 

profile report for chloropicrin (USEPA, 2013). The usage is divided into agricultural 

usage and non-agricultural/non-food usage. Approximately 10 million pounds of 

chloropicrin were applied on average annually between 1998 and 2011 to 200,000 acres 

at an overall average application rate of 50 lbs a.i./acre. 
Page 6 of 62

For agricultural usage, the top crops in terms of pounds a.i. applied during the 2007-2011 

period were strawberries (33%), tobacco (20%), tomatoes (17%), peppers (11%), and 

others (19%). The other crops include almonds, apples, beans, cabbage, caneberries, 

cantaloupes, carrots, cherries, cotton, cucumbers, wine grapes, onions, oranges, peaches, 

peanuts, plums/prunes, potatoes, pumpkins, squash, sugar beets, sweet corn, walnuts, and 

watermelon. The top states in terms of pounds a.i. applied during the same period were 

California (33%), Florida (28%), and North Carolina (20%). Other states include AL, 

AR, AK, CO, GA, ID, IN, KY, MI, NE, NM, NY, OR, PA, SC, TN, TX, VA, and WA.

For non-agricultural/non-food usage, the uses of chloropicrin in nurseries and in 

floriculture are summarized in Table 1 below. The last available year of data (2009) 

shows the highest total pound applied, with the lowest average application rate; this is 

due to the much larger application area. 

Table 1. Chloropicrin Use in Nursery and Floriculture: Total Applied and Rate per Acre

Year Pounds A.I. Applied Avg A.I. Rate (lb a.i./acre)

2003 255,000 121.6

2006 253,600 122.9

2009 433,500 105.4

Source: USDA NASS Agricultural Chemical Usage Reports, Nursery & Floriculture, 2003, 

2006, and 2009.

3.2. Antimicrobial Uses

The antimicrobial uses of chloropicrin are restricted to internal treatment of wood to 

prevent decay. Timberfume II® (Reg No. 75340-1) is registered for use as a preservative 

to prevent internal decay in wooden poles/timbers, in-place treatment of wood piles, 

poles, and timbers (using special Osmose® equipment), and for poles, piles, and timbers 

in terrestrial sites. The label also allows for the treatment of in-service wood in aquatic

sites. Square-sawn timbers (e.g. caps, stringers1

) require holes of 13/16th inch diameter at 

two (2) foot intervals from the bottom surface of timber. Pilings require four holes of 

13/16th inch diameter at 12-14 inches of depth. The first hole must be at least two (2) feet 

above the water line or the high tide mark and succeeding holes are to be 6 inches higher 

at 90o rotation from the next lower holes. A piling with 12 feet above the water line 

should be drilled with eight (8) holes for fumigant treatment. The range of application 

rates is 0.44-2.2 lbs/piling with all application occurring >2 feet above the high tide mark. 

To reduce exposure, the label requires plugging the pre-drilled holes immediately after 

application and restricts the use to outdoor structures and beams. The application rate for 

landscape timbers (3” x 5” x 8’) is 0.31 lb/timber.

Ashta Gold® (Reg No. 62531-2) is registered for use as a preservative to prevent internal 

decay in wooden poles/timbers, pilings, and glue-laminated beams. The label requires a 

minimum of four treatment holes with a diameter of 3⁄4 inch to reach the center of the 

 1 Stringers are longitudinal support beams and caps are transverse support beams in a pier, http://www.fs.fed.us/td/bridges/documents/tbi/wooddef.pdf
Page 7 of 62

wood pole. Successive holes are 6-12 inches above the previous holes. The range of 

application rates is 0.44-2.2 lbs of chloropicrin per pole. 

3.3. Typical Agricultural Methods

In general, two most frequent options of chloropicrin application methods include shank 

injection (soil injection) followed by tarping, or water sealing and drip irrigation 

(chemigation) under a pre-tarped soil surface; however, tarping is not required. For drip 

irrigation, non-tarp chloropicrin application in soil requires the placement of drip tubing 

at a minimum depth of 5 inches from surface. Post application sealing methods like 

tarping, water sealing, and compacting soil surface are fumigant management practices 

followed immediately after fumigation to contain the applied chloropicrin and reduce its 

diffusion into the atmosphere. For the production of some crops, the entire field is 

treated and referred to as a “flat fume” application or a “broadcast application.” For the 

production of other crops, fumigation occurs when planting beds are formed. A bed press 

forms a raised bed and the fumigant is injected into the bed as it is formed. The entire 

bed, or only a portion of the bed, is fumigated. This is referred to as a “strip” treatment

or a “bedded application.” The production of some ornamentals and strawberries use a 

combination of techniques. First, the entire field is fumigated and tarped. Following 

fumigation the tarps are removed, raised beds are formed, and these beds are then tarped

without further fumigation. There are a range of tarps used to reduce emission from the 

fumigated field (Table 2). Low density polyethylene (LDPE) and high density 

polyethylene (HDPE) are most commonly used for tarping. Recently, high barrier 

impermeable film (e.g., virtually impermeable film or VIP) was introduced to reduce 

emission from the fumigated field. 

Table 2. Summary of Recommended Fumigation Techniques*

Application 

Method 

Application 

Equipment

Soil 

Incorporation

Method

Field 

Treatment

Application 

Type

Tarping / Sealing Method

Water Seal Tarp

Shallow 

shank

Spray blade, 

shank

Roller, rotary 

harrow, bed 

press

Entire field, 

strip (may 

be entire 

bed or only 

part of the 

raised bed)

Flat fume or

raised bed 

None, 

standard, 

intermittent 

Untarped

LDPE

HDPE

High barrier

Deep shank Shank Roller, rotary 

harrow, bed 

press

Entire field, 

strip (entire 

bed)

Flat fume or

raised bed

N/A Untarped

LDPE

HDPE

High barrier

Chemigation Drip line None (drip 

tape(s) under 

tarp)

Entire field, 

strip (entire 

bed)

Flat fume or

raised bed

N/A Untarped

LDPE

HDPE

High barrier

*Combinations of formulation, application methods and equipment, soil incorporation methods, field 

treatments, and tarping / sealing methods vary by fumigant, crop, and geographic region. Note that not all 

potential combinations are used (e.g., water seals are not used with tarps).
Page 8 of 62

4. CONCLUSIONS FROM PREVIOUS ASSESSMENTS

4.1. Ecological Risk Assessments

The Agency has conducted multiple ecological risk assessments on chloropicrin that 

serve as a basis for this scoping document, including an amended reregistration eligibility 

decision (RED) assessment in 2009 (USEPA, 2009a) and a California red legged frog

(CRLF) litigation assessment in 2007 (USEPA, 2007c). The RED identified acute risk 

concern for all exposed aquatic and terrestrial organisms. It also identified risk via 

inhalation to birds and mammals. The CRLF assessment concluded that chloropicrin is 

likely to adversely affect the CRLF due to the potential for direct toxicity to aquatic and 

terrestrial phases of the frog, as well as the potential for indirect effects to food supply, 

habitat and designated Critical Habitat. The major ecological risk conclusions from these 

assessments are summarized in Table 3. Maximum EECs in air calculated for these 

assessments were 0.019 mg/L using the Industrial Source Complex: Short-Term Model 

(ISCTS3) with a 24-hour time-weighted average and 0.0042 mg/L using the Probabilistic 

Exposure and Risk model for Fumigants (PERFUM) with a 4-hour averaging period. 

Maximum aquatic EECs calculated using the Pesticide Root Zone Model coupled with 

the Exposure Analysis Modeling System (PRZM/EXAMS) were 79, 19, and 6.8 μg/L for 

peak, 21-day average, and 60-day average, respectively.

Table 3. Summary of Risk Concerns Identified for Chloropicrin in Previous Assessments

Birds Mammals Terr.

Plants

Terr.

Inverts Fish

Bioaccumulation Aquatic 

Inverts

Aquatic 

Plants

Groundwater 

Contamination Persistence

Degradates of 

Concern

Yes Yes Yes Yes Yes No Yes Yes Yes No None

4.2. Drinking Water Exposure Assessments

Although qualitative drinking water exposure assessments have been done in the past, the 

Health Effects Division (HED) has not conducted a dietary assessment for chloropicrin 

and no quantitative drinking water exposure assessments have been completed. The 

HED RED assessment acknowledged that chloropicrin is formed during the chlorination 

process of drinking water and noted that available monitoring data indicate that levels of 

chloropicrin in drinking water from its use as an agricultural fumigant are lower than 

those detected during the chlorination process (USEPA, 2009b).

4.3. Clean Water Act Programs

Chloropicrin is not identified as a cause of impairment for any water bodies listed as 

impaired under section 303(d) of the Clean Water Act

(http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_grou

p_id=885). No Total Maximum Daily Load (TMDL) criteria

(http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T#tmdl_by_pol

lutant) have been developed for chloropicrin.
Page 9 of 62

Some aquatic life benchmarks have been published for chloropicrin and are listed in 

Table 4 below (http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm).

These benchmarks have not yet been updated to reflect the most recent toxicity data.

Table 4. OPP Aquatic Life Benchmarks (μg/L freshwater)

Fish Invertebrates Nonvascular Plants Vascular Plants

Acute Chronic Acute Chronic Acute Acute

<8.49 -- <36 -- -- --

The Agency invites submission of water quality data for this pesticide. To the extent 

possible, data should conform to the quality standards of the OPP Standard Operating 

Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s 

Registration Review Risk Assessment and Management Process (see: 

http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf), in order to 

ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

5. ENVIRONMENTAL FATE AND TRANSPORT

Chloropicrin is a clear, colorless, nonflammable oily liquid with a strong, sharp, highly 

irritating odor and a strong lacrimator. Selected physico-chemical and environmental fate 

properties of chloropicrin are listed in Table 5. The high vapor pressure (23.8 torr at 

25○C), high Henry’s Law Constant (2.05 X 10-3 atm m3/mole), and low soil adsorption 

coefficient (Koc = 36.05 L kg-1

) on soil of chloropicrin suggest that volatilization is the 

most important environmental route of dissipation. Direct photolytic degradation (t1/2 <8 

hrs) of chloropicrin is the primary route of dissipation in the atmosphere, which suggest it 

is not a significant threat to deplete stratosphere ozone layer. Due to the fact that 

volatilization is significant and occurs rapidly, the importance of other competing 

processes, such as leaching, biotic and abiotic degradation, and adsorption to the soil 

particles, will depend on chloropicrin emission rate from fumigated fields. This is 

because emission rate determines the amount of chloropicrin left for other processes and 

its residence time in the soil system. However, if chloropicrin remains in soil, it also 

degrades in soil with half-life ranges less than one day with CO2 being the terminal 

breakdown product. Since chloropicrin has low adsorption in soil, it can potentially leach 

into groundwater and to surface water through runoff under a flooded condition. 

However, because it degrades quickly, it is unlikely to persist there when it does reach 

groundwater. The low octanol/water partition coefficient of chloropicrin also indicates 

that it is not likely to be bioconcentrated in tissues of aquatic organisms. 

Table 5. Physical and Chemical Properties of Chloropicrin

Parameter Value Source (MRID)

Chemical Identifiers

Chemical Structure --

PC Code 081501 --

Cl

Cl

Cl

NO2
Page 10 of 62

Parameter Value Source (MRID)

CAS number 76-06-2 --

Common name Chloropicrin --

SMILES Notation N(=O)(=O)C(CL)(CL)CL --

IUPAC name trichloronitromethane Merck Index

CAS name trichloronitromethane Merck Index

Molecular formula CCl3NO2 43613901

Physical/Chemical Parameters

Molecular weight 164.38 g/mol 43613901

Physical State Near colorless, oily liquid Merck Index

Melting point/range -69.2○C Merck Index

Boiling point/range 112○C at 757 torr Merck Index

Density 1.7 g/mL at 25○C Merck Index

Water solubility 1.612 g/L at 25○C 43613901

Vapor pressure 23.8 torr at 25○C Merck Index

Henry’s Law Constant@ 25oC 2.05 * 10-3 atm•m3/mole Kawamoto and Urano, 1989

Octanol/water partition coefficient 

(KOW)

240 Kawamoto and Urano, 1989

Persistence

Hydrolysis t1/2 No evidence of degradation at 

pH 5, 7, and 9

43022401

Photolysis t1/2 in water 1.3 days 42900201

Photolysis t1/2 in air 20 days 05007865

Aerobic Soil metabolism t1/2 0.3 days 43613901

Anaerobic aquatic metabolism t1/2 0.4 days 43759301

Laboratory Volatility Non-tarped soil maximum 

volatility 342 μg/cm2/hr; 

Tarped soil maximum 

volatility 205 μg/cm2/hr

43798601

Field Volatility Flux estimated among 16 filed 

studies: range from 0.94 to 

211 μg/m2

-s

44149201, 48087401, 47576901,

46420201, 47679301, 48085701,

47456001, 48006001, 47813901,

45112901, 48107601, 47295202,

45112902, 48033801, 47295204

47295203

Mobility

Column Leaching - Mobility chloropicrin is very mobile in 

all four soils tested

44191301 

Field Dissipation

Terrestrial Field Dissipation ≤1.0 day 43085101
Page 11 of 62

5.1. Fate and Transport in Soil and Water

The dissipation of chloropicrin in aquatic and terrestrial environments appears to be 

predominantly dependent on volatilization and to a lesser extent on leaching and 

degradation. The high vapor pressure and the high Henry’s Law Constant suggests that 

chloropicrin will volatilize from soil and water. Once volatilized, chloropicrin degrades 

rapidly into CO2 and other metabolites in the atmosphere via direct photolysis. The 

importance of other competing processes such as leaching, biodegradation, and 

adsorption to the soil particles will certainly depend on chloropicrin emission rate from 

the fumigated fields. This is because emission rate determines the amount of chloropicrin 

left for other processes and its residence time in the soil system. The biodegradation halflife of chloropicrin is 0.3 days with carbon dioxide being the terminal breakdown product 

(MRID 43613901). Also, a cursory review of literature data (Wilhelm et al., 1996; Gan 

et al., 2000) shows that major metabolic pathways occurs through successive reductive 

dehalogenation of chloropicrin to nitromethane:

CCl3NO2 → HCCl2NO2 → H2CClNO2 → H3CNO2 → CO2

Degradation of chloropicrin in soil follows first-order kinetics. Wilhelm et al. (1996) 

estimated the half-life of 4.5 days for chloropicrin in sandy loam soil with a rate 

equivalent to 500 lbs/Acre following the Agency’s Pesticide Assessment Guidelines.

Chloropicrin is highly soluble in water and weakly retained by soil. The supplemental 

terrestrial field dissipation studies (MRID 43085101) were conducted in California, 

applying chloropicrin to bare fallow soils at the rates of 665 lbs and 792 lbs a.i/acre 

through chisel injection followed by tarping with 1 mL polyethylene tarps for 48 hours.

The calculated field dissipation half-life was less than 21.7 hours. Volatilization of 

chloropicrin from applied fields may have resulted in short half-lives in the field 

dissipation study. Concentrations of chloropicrin at the 24-, 36-, and 48-inch depths 

increased to a maxima of 593.0, 230.5, and 75.2 ppm, respectively; times of maximum 

concentration were 12, 24, and 48 hours, respectively, after removal of the tarp.

The high Henry’s Law Constant (2.05 x 10-3 atm M3

/mole) and rapid photohydrolysis of 

chloropicrin suggest that volatilization and rapid degradation are the primary 

environmental routes of dissipation from surface water. The calculated half-life of 31.1 

hours for in aqueous solution (pH 7) when irradiated with xenon light source forming 

carbon dioxide, chloride, nitrate and nitrite (MRID 42900201). In the absence of light, 

chloropicrin did not hydrolyze in sterile aqueous buffered solution under acidic to 

alkaline pH (MRID 43022401). 
Page 12 of 62

Soil adsorption coefficient (Koc) of chloropicrin cannot be estimated from the batch 

equilibrium study. Due to the rapid volatilization of chloropicrin, it is unlikely that an 

equilibrium of chloropicrin in the batch equilibrium will be reached. The Koc of 

chloropicrin was estimated using the EPA’s computer model PCKOCWIN v1.66 of 

EPISUITE. EPI's Koc estimations are based on the Sabljic molecular connectivity 

method. The estimated Koc of chloropicrin is 36.05 ml/g. Chloropicrin’s high water 

solubility (1621 mg/L) and low Koc of 36.05 ml/g suggest its high mobility in the 

environment. The high solubility and low soil absorption of chloropicrin can result in 

movement of it downward to groundwater with water infiltration under an intense rainfall 

or continuous irrigation right after chloropicrin application. A supplemental leaching 

study (MRID 44191301) demonstrated that chloropicrin was very mobile in all four soils

tested.

5.2. Movement in Wood

Movement of chloropicrin vapor in wood (diffusion rate) depends on wood permeability, 

moisture content, grain direction, and ambient temperature (MRID 00013189). The 

longitudinal diffusion rates in Douglas Fir wood were temperature and moisture 

dependent and ranged from 1.39-1.49 , 1.55-2.76, and 4.22-5.29 * 106 cm

2

sec-1 at 11, 

21, and 32 oC, respectively. The diffusion rate generally increases with increasing 

temperature and moisture content of wood (MRID 00013189). In creosoted Southern 

Pine wood, chloropicrin moved up to 36 inches both upwardly and downwardly. This 

movement occurred in a few days versus a service life of years, and the study author 

indicates equal movement in above-ground railroad ties, caps, and stringers (MRID 

00013177).

5.3. Fate and Transport in Air

In a review of the environmental fate of chloropicrin, Kollman (1990) noted that 

chloropicrin was likely to have relatively short persistence in the atmosphere. 

Chloropicrin was found to be susceptible to direct photolytic degradation in air. 

Laboratory simulation of exposure to artificial sunlight found that it degraded with a halflife of 20 days (MRID 05007865). However, a later study using a light source that better 

simulated the spectral intensity of sunlight found chloropicrin to photolyze much more 

rapidly, with an estimated atmospheric half-life of 3.4 to 8 hours in direct sunlight (Carter 

et al., 1997), leading to an estimate of 1 day for its atmospheric lifetime. 

The major degradation products were phosgene (carbonyl chloride) and nitrosyl chloride, 

which rapidly photolyze to reactive products NO and Cl• (Carter et al., 1997). Continued 

oxidation of the chloropicrin photolysis products would eventually produce CO2, NO2, 

N2O4, and Cl2 (Ecotoxnet, 2001). Phosgene has been detected in air downwind from a 

field application of chloropicrin (Woodrow et al., 1983), consistent with the results of 

laboratory photodegradation studies.

Although chloropicrin has significant aqueous solubility, its high vapor pressure results in 

limited partitioning into water; thus its Henry’s Law Constant, 2.05 x 10-3 atm m3/mol is 
Page 13 of 62

comparable to that of long-lived atmospheric vapors such as elemental mercury.

Washout by rainfall would occur, but not at a rate likely to cause a significant reduction 

in the atmospheric half life of chloropicrin estimated from direct photodegradation. 

Similarly, uptake and subsequent degradation in soils and oceans would occur, but rates 

of these processes would likely be limited by atmospheric delivery to the soil or water 

interface, and hence approximate rates estimated for methyl bromide (Shorter et al., 

1995; Yvon and Butler, 1996).

An overall atmospheric lifetime for chloropicrin can be computed using the procedure 

followed by USEPA 2005b, in which an overall ‛total lifetime’ is computed from 

estimates of lifetimes computed from photodegradation, oceanic uptake and terrestrial 

uptake:

1/τtotal = 1/τp + 1/τo + 1/τs

where τp, is the atmospheric lifetime associated with processes of direct and indirect 

photo and chemical degradation and precipitation scavenging; and τo ,and τs are lifetimes 

associated with uptake by oceanic and terrestrial surfaces, respectively.

The atmospheric lifetime of chloropicrin in the atmosphere was estimated to be 1 day 

(0.0027 years), based on the published photodegradation rate (Carter et al., 1997). If 

atmospheric lifetimes of 2.7 and 3.4 years are assumed for oceanic and terrestrial uptake 

and degradation processes (from methyl bromide), the estimate of atmospheric lifetime 

for chloropicrin remains 0.0027 years.

The highly toxic gas phosgene (once used as a chemical warfare agent) is a major 

photodegradation product of chloropicrin. Phosgene is resistant to both direct and 

indirect photochemical degradation processes in the atmosphere (Grosjean, 1991; Helas 

and Wilson, 1992), but it is extremely reactive with water, hydrolyzing rapidly to carbon 

dioxide and hydrochloric acid (Manoque and Pigford, 1960). The dominant process 

removing phosgene from the atmosphere is its reaction with liquid water droplets (fog, 

clouds, and rain), with a tropospheric lifetime estimated at 10 hours to 1 day (Manoque 

and Pigford, 1960). Despite its short atmospheric half life, phosgene has been commonly 

detected in air, especially in urban/industrial areas, with typical concentrations of 80 to 

130 ng/m3 (WHO, 1998). Phosgene is a widely used precursor in the chemical industry, 

with 3 x 106 metric tons produced and used annually (WHO, 1998). Phosgene is also 

formed in the atmosphere by the photochemical oxidation of chloroethylenes, with 

generation rates estimated to be 350,000 metric tons annually (Singh, 1976). Phosgene 

generation by conversion of 100% of chloropicrin used agriculturally in the U.S. would 

amount to about 6000 metric tons annually (based on U.S usage of 9000 metric tons/year 

(NASS, 2005). Even with such unrealistic conversion assumptions, chloropicrin usage 

appears to be a minor source of atmospheric phosgene relative to other sources. 

Additionally, phosgene is expected to quickly degrade, hydrolyzing to CO2, HCl, and 

NOCl, producing NO, N2O4, and Cl2 (MRID 05007865).
Page 14 of 62

The reactive byproducts of chloropicrin photolysis, in particular chlorine free radicals and 

NOx, could lead to the generation of tropospheric ozone, although its potential (on a per 

molecule basis) for contributing to the generation of ozone in polluted urban atmospheres 

is no greater than the typical organic air pollutants contributing to the problem (Carter et 

al., 1997). Therefore, the stratospheric ozone depletion will not be a concern with the use 

of chloropicrin as a fumigant based on its ozone depletion potential of 5.6*10-5.

5.4. Transformation Products

The major degradates of chloropicrin in submitted environmental fate studies were 

chloronitromethane, nitromethane (in anaerobic aquatic), carbon dioxide (in aerobic soil), 

phosgene and nitrosyl chloride (in air photolysis). A variety of minor degradates were 

observed in the some studies. Table 6 summarizes the transformation products of 

chloropicrin and their maximum amounts formed.

Table 6. Chloropicrin and Its Major Environmental Degradates

Code Name/ 

Synonym

Chemical

Name

Chemical 

Structure

Study 

Type

Reference

(MRID)

Maximum 

%AR 

(day)

Final 

%AR 

(study 

length)

PARENT

Chloropicrin

Trichloromethane

Formula:

CCl3NO2

MAJOR/MINOR TRANSFORMATION PRODUCTS

Nitromethane Formula: CH3NO2

Aerobic 

soil 43613901 2% (24 d) 2% (24

d)

Anaerobic 

aquatic 43759301

57.3% (1 d)

(53.4% 

water,

3.3% soil)

n.d. (54

d)

Column 

Leaching 44191301 3.7%

Chloronitromethane Formula:

CH2ClNO2

Anaerobic 

aquatic 43759301

53.1% (4 

hrs)

(51.5% 

water,

1.6% soil)

0.1%. 

(54 d)

Aerobic 

Soil 43613901 3.8% (14 d) 1.6% 

(24 d)

Column 

Leaching 44191301 12%

Cl

Cl

Cl

NO2

H

H

H

NO2

Cl

H

H

NO2
Page 15 of 62

Code Name/ 

Synonym

Chemical

Name

Chemical 

Structure

Study 

Type

Reference

(MRID)

Maximum 

%AR 

(day)

Final 

%AR 

(study 

length)

Dichloromethylhydroxylamine

Formula:

CH3Cl2NO

Column 

Leaching 44191301 16.4%

Carbon dioxide Formula: CO2

Aerobic 

Soil 43613901 69% (24 d) 69% (24 

d)

Anaerobic 

aquatic 43759301 4.1% (24 d) 4.1% 

(24 d)

Aquatic 

Photolysis 42900201

1.43e-4

(Mol/L)

(108 hr)

1.43e-4

(Mol/L)

(108 hr)

Phosgene Formula: COCl2

Air 

Photolysis 05007865 71.7%

(70 d)

71.7%

(70 d)

Nitrosyl Chloride Formula: NOCl Air 

Photolysis 05007865 41.7%

(38 d)

32%

(70 d)

Carbonate Formula: CO3

-2 Aerobic 

Soil 43613901 2% (21 d) 1.5% 

(24 d)

Bicarbonate Formula: HCO3

- Aquatic 

Photolysis 42900201

5.73e-4

(Mol/L)

(108 hr)

5.73e-4

(Mol/L)

(108 hr)

Nitrate Formula: NO3

- Aquatic 

Photolysis 42900201

9.99e-5

(Mol/L)

(84 hr)

9.23e-5

(Mol/L)

(108 hr)

Nitrite Formula: NO2

- Aquatic 

Photolysis 42900201

1.06e-4

(Mol/L)

(108 hr)

1.06e-4

(Mol/L)

(108 hr)

Chloride Formula: Cl Aquatic 

Photolysis 42900201

2.05e-3 

(Mol/L) 

(108 hr)

2.05e-3 

(Mol/L) 

(108 hr)

Notes: A n.d. means “not detected”

6. RECEPTORS

Acute (short-term) and chronic (long-term) toxicity information is characterized based on 

registrant-submitted studies. Many of these studies were submitted and reviewed 

subsequent to the last assessment. A review of the open literature on chloropicrin will 

HO

Cl

Cl

NH2

O C O

O

O

O

HO

O

O

N

O O

O

N

O

O

Cl
Page 16 of 62

also be conducted at the time of the risk assessment. Reported ecological incidents 

associated with chloropicrin are summarized below in Section 6.3.

Table 7 and Table 8 provide summaries of the aquatic and terrestrial taxonomic groups,

respectively, and surrogate species tested to characterize the potential acute and chronic 

ecological effects of chloropicrin. Based on the available ecotoxicity information, 

chloropicrin is highly to very highly toxic to aquatic species on an acute exposure basis. 

Chronic aquatic toxicity has not been tested. Chloropicrin is toxic to mammals and birds

via inhalation. Acute toxicity to mammals is also evident via oral exposure. 

Chloropicrin is practically nontoxic to honey bees via acute contact exposure; other 

routes of exposure have not been tested. Toxicity of chloropicrin to terrestrial plants was 

tested via vapor exposure and toxicity was observed in a vegetative vigor study but not in 

a seedling emergence study. Toxicity to terrestrial species has primarily been tested via 

inhalation or vapor exposure, the main exposure route of concern due to the high 

volatility of chloropicrin. Additionally, application of chloropicrin is pre-plant via soil 

injection or drip irrigation rather than spray application so exposure to terrestrial animals 

via diet is unlikely.

Beneficial soil organisms exposed within the treated area are not considered in this 

assessment as chloropicrin is intended to be a soil sterilant. However it is expected that 

burrowing animals or beneficial soil invertebrates near treated areas may be affected if 

there is lateral transport through soils. 

Toxicity data with co-formulated products conducted with laboratory mammals and open 

literature data with non-mammalian species will be examined during the registration 

review process to determine any additive or synergistic toxicity which may be accounted 

for in the ecological assessment.

6.1. Effects to Aquatic Organisms

Table 7. Summary of Aquatic Toxicity Studies for Chloropicrin 1

Taxonomic 

Group

Study 

Type

Surrogate Species Toxicity Value

(all units in terms 

of mg/L measured 

active ingredient)

Acute 

Toxicity 

Classification 

Source

(MRID)

Freshwater 

fish2

Acute

Rainbow trout

(Oncorhynchus 

mykiss)

LC50 = 0.011 Very highly 

toxic 48442405

Bluegill sunfish

(Lepomis 

macrochirus)

LC50 = 0.050 Very highly 

toxic 48442406

Chronic -- No data -- --

Freshwater 

invertebrates

Acute Daphnia magna EC50 = 0.12 Highly toxic 48442401

Chronic -- No data -- --
Page 17 of 62

Taxonomic 

Group

Study 

Type

Surrogate Species Toxicity Value

(all units in terms 

of mg/L measured 

active ingredient)

Acute 

Toxicity 

Classification 

Source

(MRID)

Estuarine/ 

marine fish

Acute

Sheepshead minnow 

(Cyprinodon 

variegatus)

LC50 = 0.10 Highly toxic 48442402

Chronic -- No data -- --

Estuarine/ 

marine 

invertebrates

Acute

Eastern oyster 

(Crassostrea 

virginica)

EC50 = 0.010 Very highly 

toxic 48442404

Acute Mysid shrimp 

(Mysidopsis bahia) LC50 = 0.027 Very highly toxic 48442403

Aquatic 

plants and 

algae

Vascular Duckweed 

(Lemna gibba)

NOAEC = 0.00031 

EC50 = 0.0065

Very highly 

toxic 48442801

Nonvascular -- No data -- --

1 Note: all aquatic toxicity data reported here was submitted and reviewed subsequent to the most recent update of the 

OPP aquatic life benchmarks.

2 Freshwater fish may be surrogates for aquatic-phase amphibians.

6.2. Effects to Terrestrial Organisms

Table 8. Summary of Terrestrial Toxicity Studies for Chloropicrin

Taxonomic 

Group

Study 

Type

Surrogate 

Species

Toxicity Value

(all units in terms of 

measured active 

ingredient)

Acute 

Toxicity 

Classification

Source

(MRID)

Birds1

Acute oral -- No data -- --

Sub-acute 

dietary -- No data -- --

Chronic -- No data -- --

Acute 

inhalation -- No data -- --

Subchronic

inhalation

Bobwhite 

quail (Colinus 

virginianus)

NOAEC = 0.00065 mg/L

LOAEC = 0.0020 mg/L

Endpoint: microscopic 

changes in respiratory tract

NA 48442803

Mammals

Acute oral

Laboratory rat 

(Rattus 

norvegicus)

LD50 = 37.5 mg/kg-bw Highly toxic 05014376

Acute 

inhalation Laboratory rat LC50 = 0.114 mg/L -- 45117902
Page 18 of 62

Taxonomic 

Group

Study 

Type

Surrogate 

Species

Toxicity Value

(all units in terms of 

measured active 

ingredient)

Acute 

Toxicity 

Classification

Source

(MRID)

Chronic

inhalation Rabbit

NOAEC = 0.003 mg/L

LOAEC = 0.008 mg/L

Maternal endpoints: 

mortality, decreased bw, 

decreased food 

consumption

Developmental endpoints: 

abortions, decreased fetal 

weight

NA 42740601

Insects Acute 

contact

Honey bee 

(Apis mellifera 

L.)

LD50 = >100 μg/bee Practically 

nontoxic 48442407

Terrestrial 

plants

Seedling 

Emergence

(vapor 

exposure)

Monocot –

corn & 

ryegrass

NOAEC = 0.068 mg/L

EC25 = >0.068 mg/L

Endpoint: None

-- 48442802

Dicot –

cucumber, 

oilseed rape, 

soybean, & 

sunflower

NOAEC = 0.068 mg/L

EC25 = >0.068 mg/L

Endpoint: None

-- 48442802

Vegetative 

Vigor

(vapor 

exposure)

Monocot -

ryegrass

NOAEC = 0.0070 mg/L

EC25 = 0.061 mg/L

Endpoint: plant dry weight

-- 48442802

Dicot – oilseed 

rape

EC05 = 0.00040 mg/L

EC25 = 0.0021 mg/L

Endpoint: plant dry weight

-- 48442802

1 Birds represent surrogates for terrestrial-phase amphibians and reptiles.

The submitted avian inhalation study (MRID 48442803) was conducted using 4-hour 

exposures for five consecutive days with a subsequent 14-day observation period. The 

concentrations tested were sublethal and the most sensitive toxicity endpoint observed 

was microscopic changes in the respiratory tract. A decrease in body weight was 

observed at the highest test concentration (0.0044 mg/L) during the exposure period only. 

An acute avian inhalation study is needed to establish an LC50 to be used in the risk 

assessment to calculate risk quotients.

There are no data on chronic toxicity to avian species. This data would be useful to 

assess risk of growth and reproductive toxicity to birds resulting from chloropicrin vapor 

inhalation. However, EFED is not requesting chronic avian inhalation toxicity data at 

this time due to feasibility considerations. Instead, a weight of evidence approach will be 

used to characterize potential chronic risk to birds. Chronic mammalian data will be used 

in this approach where appropriate. Sub-lethal effects from acute exposure studies will 

also be considered.

In the vegetative vigor study (MRID 48442802), the most sensitive endpoint was dry 

weight for oilseed rape. However, the study author discounted this endpoint due to 
Page 19 of 62

“mechanical damage” to the plants incurred during handling. Insufficient information 

was provided to determine the impact of the mechanical damage, and whether growth 

inhibition was also a factor. The data followed a clear dose-response pattern. Therefore, 

the oilseed rape data will be considered suitable for quantitative use in risk assessment in 

the absence of additional information demonstrating why it should not be used. If 

additional data submitted show greater sensitivity on another species, then that data will 

be used in place of the oilseed rape data. The study used 6-hour exposure periods on two 

consecutive days. 

6.3. Ecological Incidents

Three databases were searched for ecological incidents possibly associated with 

chloropicrin: the Ecological Incident Information System (EIIS), aggregate incident

reports, and Avian Incident Monitoring System (AIMS). The EIIS is an OPP database 

that houses ecological incidents that have been reported to the Agency. When available, 

EIIS includes date and location of an incident, type and magnitude of effects observed in 

various species, use(s) of pesticides known or suspected of contributing to the incident, 

and results of any chemical residue analysis or other analyses conducted during incident 

investigation. EIIS incidents are categorized according to the certainty that the incident 

resulted from pesticide exposure. The Avian Monitoring System (AIMS) is a database 

administered by the American Bird Conservancy that contains publicly available data on 

reported avian incidents involving pesticides. Many of the incidents listed in this 

database are also in the EIIS. The aggregate incident reports provide counts of ecological 

incidents considered “minor.” These are reported to the Agency quarterly by registrants.

EIIS returned four incidents attributed to chloropicrin use, including one aquatic incident 

and three terrestrial plant incidents (USEPA, 2007a). The aquatic incident involved an 

accidental misuse in which chloropicrin was spilled into a waterway from an irrigation 

system and 1,000 fish were killed. It was considered highly probable that this incident 

was attributable to the spill. Two of the terrestrial plant incidents involved damage to 

apple and watermelon crops planted in fields treated previously with chloropicrin 

formulations registered for those uses. The damage was attributed to chloropicrin with 

probable and possible certainty, respectively. The third terrestrial plant incident involved 

damage to conifer seedlings at a nursery attributed with possible certainty to vapor drift 

following a fumigation with chloropicrin. See Table 9 for a list of the incidents reported 

in EIIS. As of April 11, 2013, AIMS identified no ecological incidents involving 

chloropicrin. 

Table 9. Incidents Reported in EIIS for Chloropicrin

Incident # Date

County,

State 

Certainty 

Code1

Legality 

Code2 Formul.

3

Appl. 

Method Total Magnitude

Terrestrial Plants

I020627-022 9/26/2001

Thurston,

WA 2 UN N/R Fumigation

Damage to conifer

seedlings from vapor 

drift

I007358-001 1/1/1998 WA 3 RU N/R N/R

Damage to apple trees 

planted in a recently 

treated field
Page 20 of 62

Incident # Date

County,

State 

Certainty 

Code1

Legality 

Code2 Formul.

3

Appl. 

Method Total Magnitude

I014702-076 9/1/2003

San 

Joaquin,

CA 2 RU RTU Broadcast

Mortality of 91 acres of 

watermelon seedlings 

planted in a recently 

treated field

Aquatic

I016738-016 9/1/2005

Santa Cruz,

CA 4 MA EC Drip 1000 fish deaths 1 Certainty Code: 0=Unrelated, 1=Unlikely, 2=Possible, 3=Probable, 4=Highly Probable. N/R=Not Reported

2 Legality Code: RU=Registered Use, M=Misuse, MA=Misuse (Accidental), MI=Misuse (Intentional), UN=Unknown 3 RTU=Ready To Use, EC=Emulsifiable Concentrate

The number of documented incidents in EIIS is believed to be a very small fraction of 

total morbidity and mortality caused by pesticides for a variety of reasons. Incident 

reports for non-target organisms typically provide information only on mortality events 

and plant damage. Sub-lethal effects in organisms such as abnormal behavior, reduced 

growth and/or impaired reproduction are rarely reported, except for phytotoxic effects in 

terrestrial plants. An absence of reports does not necessarily equate to an absence of 

incidents given the nature of the incident reporting.

In addition to the incidents recorded in EIIS, registrants have reported minor chloropicrin 

incidents to the Agency in aggregate reports. Registrants reported three minor plant 

incidents and one minor wildlife incident between 2005 and 2012. Unless additional

information on these aggregated incidents becomes available, they will be assumed to be 

representative of registered uses of chloropicrin in the risk assessment.

7. EXPOSURE PATHWAYS OF CONCERN

7.1. Agricultural Uses

The environmental fate properties of chloropicrin indicate that volatilization, runoff, and 

leaching represent potential transport mechanisms to aquatic and terrestrial organisms. 

Due to the application methods of soil injection and drip irrigation, dietary exposure to 

terrestrial animals is not expected. Drinking water and inhalation exposure pathways 

were screened using the SIP (Screening Imbibition Program) and STIR (Screening Tool 

for Inhalation Risk) screening methods (see Appendix A. SIP and STIR Results for 

details). SIP and STIR are described in detail at: 

http://www.epa.gov/oppefed1/models/terrestrial/index.htm.

Although exposure via contaminated drinking water is possible for terrestrial animals, the 

main route of exposure of terrestrial animals to chloropicrin is expected to be through 

inhalation. For birds, based on chloropicrin’s vapor pressure and calculations using 

STIR, the maximum 1-hour vapor inhalation dose for birds is 26,500 mg/kg-bw. By 

contrast, based on chloropicrin’s solubility limit and calculations using SIP, the upper 

bound daily drinking water intake dose for a bird is 1,306 mg/kg-bw. Multiplying the 

STIR estimate of one hour by 12 (to match the daily exposure duration of the SIP 

estimate) yields 318,000 mg/kg-bw, which is two orders of magnitude more than the 

potential drinking water dose. While these estimates are highly conservative as they do 
Page 21 of 62

not account for dissipation or degradation over the exposure period and they assume that 

the entire dose is retained in the exposed animals, the relative magnitudes of exposure via 

the two routes provide useful information. For chloropicrin, this suggests that the 

potential daily inhalation exposure of a bird is substantially greater than the potential 

daily drinking water exposure for a bird indicating that inhalation exposure may be of 

greater concern. The same pattern is seen the model estimates for mammals. 

Additionally, acute oral and acute inhalation toxicity data are available for the laboratory 

rat (MRIDs 05014376 and 45117902, respectively). The data indicate that for mammals, 

chloropicrin is more toxic via inhalation exposure than via oral exposure (oral LD50 = 

37.5 mg/kg-bw, acute inhalation LD50 3.1 mg/kg-bw [converted in STIR from LC50

0.114 mg/L]). Therefore, any risks (and mitigation measures implemented to reduce 

risks) associated with terrestrial animal exposure to chloropicrin via inhalation are 

expected to be protective of other potential routes of exposure (including via drinking 

water), and the risk assessment for terrestrial animals and chloropicrin will focus on risks 

associated with inhalation. 

Exposure in aquatic environments may occur as a result of runoff and leaching. While 

chloropicrin is highly volatile, it is also highly soluble. Therefore, it is expected to reach 

surface water and has the potential to impact aquatic species. Maximum aquatic EECs 

calculated using PRZM/EXAMS in previous assessments (USEPA 2007c and 2009a) 

were 79, 19, and 6.8 μg/L for peak, 21-day average, and 60-day average, respectively.

7.2. Antimicrobial Uses

For antimicrobial use as a wood treatment, no environmental exposure is expected and 

therefore de minimis risk is anticipated. The volume of exposure from treated utility 

poles, pilings, and landscape timbers is negligible and the Antimicrobial Division is not

conducting any further assessment of risk.

8. ANALYSIS PLAN

8.1. Soil Fumigation: Stressors of Concern

Ecological Risk Assessment

The primary stressor of ecological concern for terrestrial organisms is chloropicrin. 

Additionally, chloropicrin’s photodegradation products phosgene (carbonyl chloride) and 

nitrosyl chloride are recognized to be highly toxic gases. Both of these degradates are 

expected to quickly degrade, hydrolyzing to CO2, HCl, and NOCl, producing NO, N2O4, 

and Cl2 (MRID 05007865). Therefore, these degradates are expected to be short-lived. 

For this reason, only chloropicrin will be considered as a stressor of concern in the 

assessment of risk via inhalation to terrestrial organisms.

Similarly, the stressor of concern for aquatic organisms is chloropicrin only.
Page 22 of 62

Drinking Water Assessment

Only qualitative drinking water exposure assessments have been completed for 

chloropicrin to date. If a dietary assessment is needed in the future, EFED will provide 

the drinking water exposure assessment and determine the stressors of concern in 

conjunction with HED.

8.2. Soil Fumigation: Measures of Exposure 

EFED will use standard available models to evaluate potential exposures to aquatic and 

terrestrial organisms as described at 

http://www.epa.gov/pesticides/science/models_db.htm. 

The Agency is aware of monitoring conducted by federal and state agencies and this 

information will be considered in the assessment to the extent that data on chloropicrin

are available. In monitoring conducted in urban and rural communities near agricultural 

sites where chloropicrin was being applied in Monterey and Santa Cruz Counties, the 

California Air Resources Board observed concentrations of chloropicrin to range from 

undetected (<30 ng/m3

) to 14000 ng/m3, with a range of 8-week average concentrations 

of 406 to 2270 ng/m3. Chloropicrin was undetected in only 7 of 192 samples (CARB 

2004). Similar monitoring in Kern County found much lower levels of chloropicrin.

Aquatic Exposure Modeling

The models used to predict aquatic estimated environmental concentrations (EECs) are 

the Pesticide Root Zone Model coupled with the Exposure Analysis Modeling System 

(PRZM/EXAMS) publically available at: 

http://www.epa.gov/oppefed1/models/water/pe5_user_manual.htm. The PRZM/EXAMS 

Standard Pond scenario will be used to estimate the aquatic EECs in surface water. Since 

both surface chemigation and incorporated chemigation and injection application

methods for chloropicrin application exist, two separate runs will be conducted for each 

crop scenario addressing the surface and incorporated applications. The PRZM 

volatilization algorithm will be used to address both chloropicrin’s upward movement in 

soil to the runoff extraction zone and escape to the atmosphere. 

Terrestrial Exposure Modeling

Screening level calculations have suggested that the inhalation exposure pathway may be 

significant for terrestrial wildlife. This exposure pathway is far more significant than 

potential exposure via drinking water and will be further considered at the time of the risk 

assessment. Dietary exposure to terrestrial wildlife is not anticipated to result in LOC 

exceedances.

Chloropicrin acute exposures of the birds, mammals, terrestrial invertebrates, and plants

through inhalation and vapor exposure are determined using the EECs from atmospheric 

dispersion models relying on the input of chloropicrin atmospheric flux measurements 
Page 23 of 62

from the collection of field volatility (flux) studies. For detailed descriptions of the field 

volatility studies reviewed for chloropicrin, see Appendix B. Field Volatility Study 

Summaries. Consistent with the aquatic exposure assessment, the terrestrial ecological 

risk assessment will assess two separate scenarios addressing surface and incorporated 

application of chloropicrin. The Agency’s recommended screening dispersion model for 

the near field, the American Meteorological Society/EPA Regulatory Screening Model 

(AERSCREEN), will be used to generate Tier I EECs. The Tier I analysis will consider 

the maximum flux rate for each application method from the collection of chloropicrin 

flux studies and worst-case meteorological conditions (light winds and stagnant 

conditions) to calculate peak air EECs, representing one-hour average concentrations. 

Documentation on the AERSCREEN model is available at 

http://www.epa.gov/scram001/dispersion_screening.htm. The exposure scenario 

evaluated in the Tier 1 analysis will assume that the terrestrial receptors are directly 

downwind from the emissions source. This is illustrated in Figure 1 below.

Figure 1. Schematic showing soil fumigant air exposure scenario due to volatilization and

subsequent release from soil evaluated in Tier 1 analysis.

If the Tier 1 EECs for either surface or incorporated applications result in an exceedance 

of the LOC, EECs will be further examined using the Tier 2 model, the Probablistic

Exposure and Risk Model for Fumigants (PERFUM). PERFUM is parameterized by a 

time series of flux data obtained from field volatility studies. PERFUM considers these 

flux values with a robust statistical sampling of meteorological data from points within

rings surrounding a treated field (usually 5 years of hourly meteorological data). The 

current version of PERFUM processes estimated air concentrations from EPA’s 

previously recommended atmospheric dispersion model in the near field, the Industrial 

Source Complex Short-Range Model, Version 3 (ISCST3). ISCST3 has since been 

replaced by the refined mode of AERSCREEN, the AERMOD model, as the 

recommended refined dispersion model in the near field. However, both ISCST3 and 

AERMOD are similar by that they both use Gaussian plume dispersion principles. The 

framework for PERFUM is illustrated in Figure 2 below. Estimated air concentrations 

are calculated and binned by percentile distributions within each ring and averaging time 

period. First, a peak one-hour averaging period will be used to calculate air EECs. If 

Wind, Dispersion, 

and 

Accumulation 

of Vapors or Gas

Volatilization of 

residues in soil

Soil incorporated and 

chemigation fumigant 

application
Page 24 of 62

necessary, a higher averaging period equivalent to the exposure duration in toxicity 

studies will be used to characterize the RQs resulting from utilizing the one-hour peak 

EECs. The highest 90th percentile estimated air concentration from all averaging periods 

from the receptor ring closest to the edge of the field will be considered as the upperbound EEC to determine the RQ. The PERFUM model is publically available on the web 

from the follow link:

http://www.exponent.com/projectdetail.aspx?project=450. For this soil fumigant

assessment, maximum air exposure will occur at the edge of the field corresponding to 

the where chloropicrin mass emissions from the treated field will accumulate to 

maximum levels along the fetch of wind blowing over the treated field.

Figure 2. Illustration of the spatial and temporal aspects of the source to receptor

configuration in PERFUM. The wind rose (left) illustrates the frequency distribution of 

variations in wind speed and wind direction that PERFUM accounts for in the transport of 

the vapor plume from the treated source to receptors (right).

All modeling scenarios will be parameterized based on field volatility flux data 

normalized to an 80 acre field. 

For exposure to plant seedlings, TerrPlant will be used unless other approved terrestrial 

plant exposure models are available. Although TerrPlant EECs are based on runoff, the 

conservative values calculated by TerrPlant will capture the overall exposure of plant 

seedlings in the soil, whether it occurs from diffusion in the gas phase or runoff of 

chloropicrin. The Agency is currently developing a replacement model for TerrPlant. If 

the replacement has been approved prior to the initiation of the risk assessment, this new 

model will be used instead.

In addition, chloropicrin dermal and inhalation exposure to organisms residing in soil 

may occur underneath and nearby fields treated with chloropicrin. An upper-bound 

exposure scenario can be extrapolated from the PRZM crop scenarios discussed above. 

Treated 

Field

Receptor 

Rings
Page 25 of 62

8.3. Measures of Effect 

Toxicity data presented in Section 6 of this problem formulation will be used to calculate 

risk quotients. Any additional information submitted by the registrant or found in the 

open literature prior to conduct of the risk assessment will also be considered. The open 

literature studies are identified using EPA’s ECOTOXicology database (ECOTOX) 

(USEPA, 2007b), which employs a literature search engine for locating chemical toxicity 

data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of 

data can also provide insight into the direct and indirect effects of pesticides on biotic 

communities from loss of species that are sensitive to the chemicals and from changes in 

structure and functional characteristics of the affected communities.

8.4. Antimicrobial Uses

Treated utility poles2

, pilings3, and landscape timbers4 represent a de minimis amount of 

environmental exposure because of the low application rate of chloropicrin, the low areal 

density, the slow off-gassing that occurs over the long useful life of the pole, and the 

wind that disperses the off-gassed fumigant. Utility poles are treated at up to 2.2 lbs 

a.i./pole5 and are generally spaced 100-150 feet apart6. As a result, the only 

environmental exposure is release into air that occurs over time, and the service life of a 

utility pole is approximately 30-40 years.7

 Assuming an application rate of 2.2 lbs/pole, 

a minimum 30-year lifespan, 100% release from pilings into air, and uniform off-gassing,

the chloropicrin release into the atmosphere is 0.073 lb/year, or 0.0002 lb/day8. Like any 

compound that is released into the air, the presence of wind will dilute the aerial 

concentrations. Some wildlife species such as Pileated Woodpeckers9 (Dryocopus

pileatus)10 will peck the wood and Edgewater Parrots11 (Myiopsitta monachus)

12 will nest 

on poles, but the chloropicrin off-gassing is not expected to cause risk because of the low 

application rate, slow off-gassing, and wind. 

 2 A round timber of any size or length, usually used with the large end in the ground., 

http://www.fs.fed.us/t-d/bridges/documents/tbi/wooddef.pdf 3 A long, heavy timber, round or square, that is driven deep into the ground to provide a secure foundation 

for structures built on soft, wet, or submerged sites., http://www.fs.fed.us/td/bridges/documents/tbi/wooddef.pdf

4 Long pieces of square or rounded lumber, http://homeguides.sfgate.com/border-driveway-landscapetimbers-39043.html 5 Amended RED, May 2009, EPA-HQ-OPP-2007-0350-0396[1].pdf 6 http://www.sizes.com/materls/utilitypole.htm

7 MRID 00013177, http://products.construction.com/swts_content_files/1475/593095.pdf 8 2.2 lbs/pole / 30 years /365 days/year

9 S.K. Tupper, W.F. Andelt, J.L. Cummings, C. Weisner, and R.E. Harness. April 2010. Polyurea 

Elastomer Protects Utility Pole Crossarms From Damage by Pileated Woodpeckers. The Journal of 

Wildlife Management 74(3): 605-608 10 http://en.wikipedia.org/wiki/Pileated_Woodpecker 11http://www.nj.com/bergen/index.ssf/2013/03/photos_edgewater_parrot_nests_removed_from_utility_pole

s_along_the_palisades.html 12 http://en.wikipedia.org/wiki/Monk_Parakeet
Page 26 of 62

In addition, pilings for aquatic use can be treated at 0.44-2.2 lbs a.i./piling and the 

minimum treatment distance above the high tide mark is 2 feet. Treated caps and 

stringers13 (horizontal decking and support boards) in a pier are well above the water line 

and also would not create direct aquatic exposure unless rainfall leaches some 

chloropicrin which falls into a water body. However, the high Henry’s Law constant of 

2.1 x 10-3 atm m3 mol-1 (Kawamoto and Urano, 1989) indicates that any chloropicrin in 

water is likely to volatilize and not be retained in water. Like treated utility poles, the 

service life of treated wood used in piers is >25 years14 and any chloropicrin that 

dissipates from wood occurs over time into the air (MRID 00013177). Assuming an

application rate of 2.2 lbs/piling, a minimum 25-year lifespan, uniform off-gassing, and 

100 % release from pilings into air, the chloropicrin release into the atmosphere is 0.088 

lb/year, or 0.00024 lb/day15. Like any compound that is released into the air, the 

presence of wind will dilute the aerial concentrations of chloropicrin. The effect of wind 

will be higher in coastal areas with minimal or no cover, while wind is likely to have a 

lesser effect in areas that are contained. As a result, aquatic exposure is expected to be 

minimal because of the low application rate, slow off-gassing, and wind. 

Landscape timbers represent a de minimis amount of environmental exposure of 

chloropicrin because of the low application rate of chloropicrin, the low areal density, 

and the slow off-gassing that occurs over the long useful life of the timber. They are also 

expected to last 15-20 years in use16. Landscape timbers are treated at up to 0.31 lb 

a.i./timber17 and tend to be present in small quantities in individual properties. Thus, they 

are areally dispersed. As a result, the only environmental exposure is release into air that 

occurs over time. Assuming an application rate of 0.31 lbs/pole, a minimum 15-year 

lifespan, 100% release from pilings into air, and uniform off-gassing, the chloropicrin 

release into the atmosphere is 0.021 lb/year, or 0.000057 lb/day18. 

Due to the use of chloropicrin as a treatment for utility poles, pilings and landscape 

timbers, little, if any exposure (de minimis) to non-target organisms would occur. 

Therefore, no risk to non-target organisms would occur from the antimicrobial uses of 

chloropicrin. 

9. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), 

the Agency will evaluate risks to federally listed threatened and/or endangered (listed) 

species from registered uses of pesticides in registration review. The process for 

evaluating potential risks to listed species is further described at 

http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm.

 13 Stringers are longitudinal support beams and caps are transverse support beams in a pier, 

http://www.fs.fed.us/t-d/bridges/documents/tbi/wooddef.pdf 14 Koppers Timber Piling Life Expectancy Guide, www.koppers.com.au 15 2.2 lbs/piling / 25 years / 365 days/year 16 http://www.brightonservices.com/retainingwalls.html 17 2.2 lbs chloropicrin/piling * 0.8 ft3/landscape timber / 5.9 ft3/ piling 18 0.31 lbs/pole / 15 years /365 days/year
Page 27 of 62

10. Endocrine Disruptor Screening Program

Chloropicrin was not included in the first group of 67 chemicals issued an order to 

conduct Tier 1 EDSP testing nor in the second group of 109 chemicals. For additional 

information the EDSP program, visit http://www.epa.gov/endo/. 

11. PRELIMINARY IDENTIFICATION OF DATA GAPS

11.1. Environmental Fate

Table 10 identifies environmental fate studies by MRID that offer data for each guideline

requirement, study classifications and if additional data are warranted to support a risk 

assessment. EFED recommends requesting the following studies to assess the 

environmental risks associated with the use of chloropicrin for soil fumigation:

• 835.4300 – Aerobic aquatic metabolism

• 850.6100 – ECM and ILV studies in air and water

No additional environmental fate data is needed to further assess the antimicrobial uses of 

chloropicrin.

Table 10. Submitted Environmental Fate Data for Chloropicrin

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are 

additional 

data needed 

for risk 

assessment?

Justification

835.2120 Hydrolysis 43022401 Acceptable No --

835.2240 Aqueous 

photolysis

42900201 Supplemental No --

835.2410 Soil Photolysis 05007865 Acceptable No Study waived. Because 

chloropicrin is used by soil 

injections, no substantial soil 

photolysis is expected.

835.2370 Air photolysis 05007865 Acceptable No --

835.4100 Aerobic soil 

metabolism

43613901 Acceptable No

835.4200 Anaerobic soil 

metabolism

41478601 Unacceptable No Use anaerobic aquatic 

metabolism study results

835.4300 Aerobic aquatic 

metabolism

(None) (N/A) Yes A laboratory aquatic study is 

needed to determine 

chloropicrin’s residence time in 

water. See additional details 

below.

835.4400 Anaerobic 

aquatic 

metabolism

43759301 Acceptable No --
Page 28 of 62

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are 

additional 

data needed 

for risk 

assessment?

Justification

835.1230

835.1240

Adsorption/ 

desorption and 

leaching

44191301 Supplemental No --

835.1410 Volatility –

laboratory

43798601 Acceptable No --

835.6100 Terrestrial field 

dissipation

43085101 Supplemental No

850.1730

(165-4)

Fish 

bioconcentration

(None) (N/A) No Study waived, due to 

chloropicrin’s low Kow value

850.6100 Environmental 

chemistry 

methods and 

associated 

independent 

laboratory 

validation

(None) (N/A) Yes ECM and ILV studies are needed 

for methods in air and water to 

support field volatility studies 

and aquatic toxicity studies.

835.4300: Aerobic Aquatic Metabolism with Chloropicrin: An aerobic aquatic 

metabolism study with chloropicrin is necessary for risk assessment. This study will 

enable the determination of chloropicrin’s residence time in water to address the potential 

length and intensity of exposure of aquatic species to chloropicrin. The DT50 and 

residence time from this study will be used quantitatively in PRZM/EXAMS surface 

water acute EEC calculations. Since volatilization is expected to be the dominate loss 

route and sorption to sediment is expected to be minimal, this study should only measure 

chloropicrin concentrations in water and in the headspace. However, known degradates 

should be quantified to recover and track the complete material balance over the course 

of the study.

11.2. Effects

Table 11 and Table 12 identify ecological effects studies by MRID that offer data for 

each guideline requirement, as well as study classifications and whether or not further 

data are needed in order to support risk assessment. Rationale for the additional data 

requested is presented below the tables where further explanation is needed. EFED 

recommends requesting the following studies to assess the environmental risks associated 

with the use of chloropicrin for soil fumigation: 

• Aquatic

o 850.4500 – Aquatic non-vascular plant studies

• Terrestrial

o 850.4100 – Seedling emergence study

o 850.4150 – Vegetative vigor vapor exposure study with additional 

species*

o Non-guideline – Avian acute inhalation study with bobwhite quail*

o Non-guideline – Acute honey bee vapor exposure study*
Page 29 of 62

*A protocol should be submitted to the Agency for approval prior to initiating the study.

No additional environmental toxicity data is needed to further assess the antimicrobial 

uses of chloropicrin.

Table 11. Submitted Aquatic Ecological Effects Data for Chloropicrin

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are 

additional 

data needed 

for risk 

assessment?

Justification 

850.1010 Freshwater 

invertebrate 

acute toxicity

48442401 Acceptable No --

47102101 Supplemental

00130704 Supplemental

850.1025

850.1035

Saltwater 

invertebrate 

acute toxicity 

48442404 Supplemental No --

48442403 Acceptable

850.1075 Freshwater 

fish acute 

toxicity 

48442406 Acceptable No --

48442405 Acceptable

47102103 Supplemental

47102102 Supplemental

TN 0439 Supplemental

TN 0425 Supplemental

850.1075 Saltwater fish 

acute toxicity 

48442402 Acceptable No --

850.1300 Freshwater 

invertebrate 

life cycle 

(None) (N/A) No Chronic exposure to aquatic 

organisms is not anticipated as 

chloropicrin is expected to be short 

lived in the water column.

850.1350 Saltwater 

invertebrates 

life cycle 

(None) (N/A) No --

850.1400 Freshwater 

fish 

early-life 

stage

(None) (N/A) No Chronic exposure to aquatic 

organisms is not anticipated as 

chloropicrin is expected to be short 

lived in the water column.
Page 30 of 62

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are 

additional 

data needed 

for risk 

assessment?

Justification 

850.1400 Saltwater fish 

early-life 

stage 

(None) (N/A) No --

850.1500 Fish life 

cycle 

(None) (N/A) No --

850.4400 Aquatic plant 

growth:

Tier II 

vascular 

plants

48442801 Acceptable No --

850.4500 Aquatic Plant 

Growth:

Tier II algae

(None) (N/A) Yes Chloropicrin is highly soluble and 

therefore aquatic plant exposure is 

likely. Guideline compliant 

studies are needed for a full suite 

of non-vascular aquatic plants (i.e., 

green algae (Pseudokirchneriella 

subcapitata), blue-green algae 

(Anabaena flos-aquae), a 

freshwater diatom (Navicula 

pelliculosa), and a marine diatom 

(Skeletonema costatum)).

Table 12. Submitted Terrestrial Ecological Effects Data for Chloropicrin

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are

additional

data needed 

for risk 

assessment?

Justification 

850.2100 Avian oral 

toxicity

(None) (N/A) No Avian oral exposure via 

drinking water is a pathway of 

concern; however, assessment 

of risk via inhalation is 

expected to be protective.

850.2200 Avian dietary 

toxicity 

(None) (N/A) No Avian dietary exposure is not 

expected to be a significant 

exposure pathway. 

850.2300 Avian 

reproduction

(None) (N/A) No Chronic avian inhalation 

toxicity data would be useful 

for evaluating chronic risk to 

birds. However, no study is 

requested at this time due to 

feasibility considerations. A 

weight of evidence approach 

will be used to evaluate 

potential chronic risk to avian 

species.
Page 31 of 62

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are

additional

data needed 

for risk 

assessment?

Justification 

NonguidelineAvian 

inhalation

toxicity

48442803 Supplemental Yes Inhalation is the primary

exposure pathway of concern

for chloropicrin to terrestrial 

animals. A 4-hr acute avian 

inhalation study on bobwhite 

quail is needed to establish an 

LC50. The previously 

submitted study uses a subchronic 5-day exposure at sublethal exposure levels. A 

protocol should be submitted to 

the agency prior to beginning 

the study. See additional 

justification below.

850.3020 Honey bee 

acute contact 

toxicity

48442407 Acceptable No --

850.3030 Honey bee 

residue on 

foliage

(None) (N/A) No --

850.3040 Field testing 

for 

pollinators

(None) (N/A) No --

NonguidelineAcute honey 

bee vapor 

exposure 

study

(None) (N/A) Yes Exposure to vapor is the 

primary pathway of concern for 

non-target terrestrial 

invertebrates. A protocol 

should be submitted to the 

agency prior to beginning the 

study. See additional 

justification below.

850.4100 Seedling 

emergence

48442802 Supplemental Yes Soil exposure of seedlings to 

chloropicrin via runoff is a 

potential concern. The 

submitted study uses a vapor 

exposure pathway. Registrants 

are encouraged to contact the 

Agency regarding test 

considerations prior to study 

initiation.
Page 32 of 62

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are

additional

data needed 

for risk 

assessment?

Justification 

850.4150 Vegetative 

vigor

48442802 Supplemental Yes The submitted study tests 

effects of chloropicrin vapor on 

4 dicot and 2 monocot species. 

Effects were seen at the lowest 

concentration tested. Testing 

of additional species is needed

to meet the guideline 

requirement of 6 dicots and 4 

monocots and to establish a 

clear NOAEC for use in risk 

assessment. A protocol should 

be submitted to the agency 

prior to beginning the study. 

See additional justification 

below.

870.1300 Mammalian 

acute 

inhalation 

toxicity

45117902 Acceptable No --

Guideline Number: N/A (Non-Guideline Study)

Study Title: Acute Avian Inhalation

Rationale for Requiring the Data

Volatilization is the major route of dissipation for chloropicrin. Therefore, to assess acute 

risks of chloropicrin to birds, EFED recommends that the Agency require a nonguideline acute avian inhalation exposure study for chloropicrin with bobwhite quail, to 

be conducted in lieu of the 850.2100 requirement for acute avian oral toxicity studies. 

Practical Utility of the Data

How will the data be used? 

The acute avian inhalation data are needed to asses potential acute risks to birds 

associated with the inhalation route of exposure. Results of this study would be used to 

calculate acute risk quotients for birds from exposure to chloropicrin and to identify 

whether current labeling is appropriate and whether further mitigation is necessary.

The data will allow the Agency to better assess the risks to these organisms, including 

the likelihood of potential risks to endangered species, either by direct effects or by 

indirect effects such as reducing food sources to listed predators and scavengers. 

How could the data impact the Agency’s future decision-making?

If future ecological risk assessments are performed without these data, the Agency would 

have to presume risk to non-target birds, reptiles, and terrestrial-phase amphibians, 

including listed species, from use of chloropicrin. Therefore, use of chloropicrin and its 

formulated products may need to be restricted in areas where these taxa could be 

exposed. The lack of these data will limit the flexibility the Agency and registrants have 

in mitigating potential risks and could result in use restrictions for chloropicrin that are 
Page 33 of 62

unnecessarily severe. If future endangered species risk assessments are performed 

without these data, the Agency would have to assume that chloropicrin "may affect” 

birds directly and other endangered species indirectly through loss of prey. The lack of 

these data will limit the flexibility the Agency and registrants have in complying with the 

Endangered Species Act and could result in inappropriate mitigation measures. 

Guideline Number: N/A (Non-Guideline Study)

Study Title: Acute Honey Bee Vapor Exposure Study

Rationale for Requiring the Data

Due to the fate properties of fumigants, in particular their high volatility, it is expected 

that honey bees and other insect pollinators will be exposed to fumigants in the vapor 

phase. Neither of the standard Tier I toxicity studies with honey bees (i.e., acute contact 

or acute oral toxicity study for honey bees) account for exposure to vapor phase 

pesticides. Therefore, to assess risks of chloropicrin to bees, EFED recommends that the 

Agency require a non-guideline acute honey bee vapor exposure study for chloropicrin, 

to be conducted in lieu of the newly proposed requirements for oral toxicity tests 

including adult and larval honey bees. 

Practical Utility of the Data

How will the data be used?

Data from an acute honey bee vapor exposure study will be used to determine the 

potential for chloropicrin to affect non-target terrestrial invertebrates in the terrestrial 

environment. Of particular interest is quantification of a toxicity endpoint, i.e., a 4-hour 

LC50, that can be used to derive risk quotients. In the absence of vapor exposure data 

specific for honey bees, risk to terrestrial invertebrates, including listed species, will be 

assumed, and it will be impossible to determine how far from a treated site risks to 

terrestrial invertebrates remain above concern levels. 

How could the data impact the Agency’s future decision-making?

If future ecological risk assessments are performed without these data, the Agency would 

have to presume risk to non-target terrestrial invertebrates, including honey bees, from 

use of chloropicrin. Therefore, use of chloropicrin and its formulated products may need 

to be restricted in areas where terrestrial invertebrates, including honey bees, could be 

exposed. The lack of these data will limit the flexibility the Agency and registrants have 

in mitigating potential risks and could result in use restrictions for chloropicrin that are 

unnecessarily severe.

Guideline Number: 850.4150 (modified)

Study Title: Vegetative Vigor

Rationale for Requiring the Data

Due to the fate properties of fumigants, in particular their high volatility, it is expected 

that plants will be exposed to fumigants in the vapor phase. A vegetative vigor study 

with vapor exposure to chloropicrin was previously submitted to the Agency (MRID 

48442802). This study tested 4 dicot and 2 monocot species. Effects were seen at the 

lowest concentration tested, below previously modeled air exposure concentrations. The 

vegetative vigor guideline requires testing of 6 dicot and 4 monocot species. Therefore, 

testing of additional species is requested. Additionally, the study protocol should provide 
Page 34 of 62

justifications for the exposure period and test concentrations used. Justification for these 

parameters was not provided in the previous study report.

Practical Utility of the Data

How will the data be used?

Data from a vegetative vigor vapor exposure study will be used to determine the 

potential for chloropicrin to affect non-target terrestrial plants. Of particular interest is 

quantification of toxicity endpoints, i.e., a NOAEC or EC05 and an EC25 that can be used 

to derive risk quotients for listed and non-listed species, respectively. In the absence of 

vapor exposure toxicity data for additional terrestrial plant species, the lowest endpoints 

from the previously submitted study will be used in risk assessment and the resulting 

uncertainty in risk estimation will be identified.

How could the data impact the Agency’s future decision-making?

If future ecological risk assessments are performed without these data, the Agency may

have to presume risk to non-target terrestrial plants in families that were not tested, 

including listed species, from use of chloropicrin. Therefore, use of chloropicrin and its 

formulated products may need to be restricted in areas where terrestrial plants could be 

exposed. The lack of these data will limit the flexibility the Agency and registrants have 

in mitigating potential risks and could result in use restrictions for chloropicrin that are 

unnecessarily severe.

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MRID Citation

Environmental Fate and Product Chemistry Studies

05007865 Moilanen, K.W.; Crosby, D.G.; Humphrey, J.R.; Giles, J.W. (1978) Vapor-phase 

photodecomposition of chloropicrin (trichloronitromethane). Tetrahedron 34(22):3345-

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Transportation, Washington, D.C. NTIS PB-264 975.

41478601 Olsen, G.; Lawrence, L. (1990) Anaerobic Metabolism of (14 C)| Chloropicrin in Sandy 

Loam Soil: Lab Project Number: PTRL REPORT NO. 1232: PTRL PROJECT NO. 329. 

Unpublished study prepared by Pharmacology and Toxicology Research Lab. 46 p.

42900201 Moreno, T.; Lee, H. (1993) Photohydrolysis of Chloropicrin: Lab Project Number: 

BR389.1:93. Unpublished study prepared by Bolsa Research Associates, Inc. 98 p.

43022401 Chang, T. (1989) Hydrolysis Study with Chloropicrin as a Function of pH at 25 Degrees 

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MRID Citation

43085101 Ivancovich, A. (1987) Chloropicrin--Field Dissipation Study: Lab Project Number:

BR11:87.1. Unpublished study Prepared by Bolsa Research Associates. 144 p.

43613901 Hatton, C.; Shepler, K.; Ruzo, L. (1995) Aerobic Soil Metabolism of (carbon 14)-

Chloropicrin: Lab Project Number: 448W-1: 448W. Unpublished study prepared by PTRL

West, Inc. 196 p.

43759301 Hatton, C.; Shepler, K.; Ruzo, L. (1995) Anaerobic Aquatic Metabolism of (Carbon 14)

Chloropicrin: Lab Project Numbers: 449W-1: 449W. Unpublished study prepared by 

PTRL West, Inc. 200 p.

43798601 Skinner, W.; Jao, N. (1995) Laboratory Volatility of (carbon 14) Chloropicrin: Lab Project

Number: 450W-1: 450W. Unpublished study prepared by PTRL West, Inc. 99 p.

44149201 Beard, K.; Murphy, P.; Fontaine, D.; et al. (1996) Monitoring of Potential Worker 

Exposure, Field Flux, and Off-Site Air Concentration During Chloropicrin Field 

Application: (Final Report): Lab Project Number: HEH 160: RAM-10-050: F95059-527. 

Unpublished study prepared by The Dow Chemical Co. 701 p.

44191301 Skinner, W. (1996) Soil Column Leaching of (carbon-14) Chloropicrin in Four Soil Types:

Lab Project Number: 587W-1: 587W. Unpublished study prepared by PTRL West, Inc. 

230 p.

47456001 Gillis, M. Smith. G. (2002) Chloropicrin Emissions and Offsite Drift from Tarped and 

Non-tarped Fields Treated by Drip Irrigation Application Method. TriCal, Inc. Report no. 

TC350. 95pp.

45112901 Knuteson, J.; Dolder, S. (2000) Field Volatility of 1,3-Dichloropropene and Chloropicrin 

from Shallow Drip Irrigation Application of Telone C-35 (InLine) to Strawberry Beds 

Covered with VIF Tarp: Lab Project Number: 980070.01. Unpublished study prepared by 

Dow AgroSciences LLC. 331 p.

45112902 van Wesenbeck, I.; Phillips, A. (2000) Field Volatility of 1,3-Dichloropropene and 

Chloropicrin from Surface Drip Irrigation Application of InLine to Vegetable Beds Under 

Polyethylene Tarp: Lab Project Number: 990072. Unpublished study prepared by Dow 

AgroSciences LLC and Paragon Research. 304 p.

46420201 Rotondaro, A. (2004) Monitoring of Chloropicrin Emissions from Field and Greenhouse 

Drip Irrigation Applications, and Implied Worker Inhalation Exposure From Applications 

of Chloropicrin by Shank Injection, Drip Irrigation Systems and at Tree Replant Sites. 

Project Number: PRS02004, ML02/1044/CMT. Unpublished study prepared by Paragon 

Research Services, Morse Laboratories and Agvise Inc. 793 p.

47295202 Baker, F.; Arndt, T. (2007) Direct and Indirect Flux Determination of Iodomethane and 

Chloropicrin under Field Conditions Following Tarped/Raised Bed/Shallow Shank 

Injection of Midas 50:50 in Dover, FL. Project Number: 1595W, 1595W/1. Unpublished 

study prepared by PTRL West, Inc., Paragon Research Services and Pacific Ag Group. 707 

p.

47295203 Baker, F.; Arndt, T. (2007) Direct and Indirect Flux Determination of Iodomethane and 

Chloropicrin Under Field Conditions Following Tarped/Raised Bed/Shallow Shank 

Injection of Midas 50:50 in Bainbridge, GA. Project Number: 1619W, 1619W/1. 

Unpublished study prepared by PTRL West, Inc, Paragon Research Services, Pacific Ag 

Group. 590 p.

47295204 Baker, F.; Arndt, T. (2007) Direct and Indirect Flux Determination of Iodomethane and 

Chloropicrin Under Field Conditions Following Tarped/Raised Bed/Shallow Shank 

Injection of Midas 50:50 in Hart Michigan. Project Number: 1646W, 1646W/1. 

Unpublished study prepared by PTRL West, Inc, Paragon Research Services, Pacific Ag 

Group. 590 p.

47576901 Ajwa, H.; Sullivan, D. (2008) Monitoring of Chloropicrin Field Emissions from Shank 

Applications at Shallow and Deep Injection Depths. Project Number: 200801. Unpublished 

study prepared by Sullivan Environmental Consulting and University of California, Davis. 

191 p.
Page 38 of 62

MRID Citation

47679301 Rotondaro, A. (2009) Direct Flux Determination of Chloropicrin Emissions from a Drip,

Buried, Non-Tarped Application. Project Number: PRS08004. Unpublished study prepared

by Paragon Research Services, PTRL West, Inc. and Agvise, Inc. 192 p.

47813901 Ajwa, H.; Sullivan, D.; Chellemi, D. (2009) Monitoring 1,3-Dichloropropene, 

Chloropicrin and Methyl Isothiocyanate Emissions from Shank Applications at Three Sites 

Near Duette, Florida. Project Number: 2009A. Unpublished study prepared by University 

of California, Sullivan Environmental Consulting and JRF America. 114 p.

48006001 Ajwa, H.; Sullivan, D. (2010)Monitoring Methyl Bromide and Chloropicrin Field 

Emissions from Shank Applications at Shallow and Deep Injection Depths. Methyl 

Bromide Industry Panel, LLC. Study ID 200901. 574p.

48033801 Rotondaro, A.; Rotondaro, M. (2010) Direct Flux Determination of Chloropicrin

Emissions from Shank, Bedded, Non-Tarped Applications. Project Number: PRS09006, 

1978W. Unpublished study prepared by PTRL West, Inc. and Paragon Research Services 

and Agvise Laboratories, Inc. 229 p.

48085701 Ajwa, H.; Sullivan, D.; Chellemi, D. (2010) Monitoring 1,3-Dichloropropene and 

Cloropicrin Emissions from Solid-Tarp Shank Injections at Two Sites Near Fort Pierce, 

Florida. Project Number: 2009H. Unpublished study prepared by University of California 

and Sullivan Environmental Consulting. 146 p.

48087401 Ajwa, H. (2010) Chloropicrin Flux Rates for Drip Fumigation with PE and TIF Tarps, 

Water Seal and KTS at Salinas, California in September 2007. Project Number: 2007/D. 

Unpublished study prepared by University of California and Sullivan Environmental 

Consulting. 100 p.

48107601 Ajwa, H.; Sullivan, D. (2010) Monitoring of Methyl Bromide and Chloropicrin Field 

Emissions from Shank Applications (Bedded and Broadcast) and a Methyl Bromide HotGas Application under Totally Impermeable Film. Project Number: HA201001. 

Unpublished study prepared by University of California and Sullivan Environmental

Consulting. 219 p.

Ecological Effects Studies

TN 0439 McCann, J. (1972) Fish Toxicity Laboratory Report (#439) Chloropicrin Fumigant and 

Bluegill Sunfish (Lepomis macrochirus). Unpublished Study Performed by Animal 

Biology Laboratory, Beltsville, Maryland. Laboratory Project No. 439. Study Sponsor not 

Reported. Study Completed January 22, 1972.

TN 0425 McCann, J. (1971) Fish Toxicity Laboratory Report (#425) Chloropicrin Fumigant and 

Rainbow Trout (Salmo gairdneri). Unpublished Study Performed by Animal Biology 

Laboratory, Beltsville, Maryland. Laboratory Project No. 425. Study Sponsor not 

Reported. Study Completed December 5, 1971.

00130704 Cody, W.; Shema, R. (1983) Acute Toxicity of Chloropicrin to Daphnia pulex. 

(Unpublished study received May 9, 1983 under unknown admin. no.; prepared by NUS 

Corp., submitted by Chloropicrin Consortium, West Lafayette, IN; CDL:251027-B)

42740601 York, R. (1993) Inhalation Developmental Toxicity Study in New Zealand White Rabbits: 

Chloropicrin: Lab Project Number: 656-009. Unpublished study prepared by International 

Research and Development Corp. 179 p.

43391901 Schardein, J. (1994) Two Generation Inhalation Reproduction/Fertility Study in Rats: 

Chloropicrin: Lab Project Number: 656-011. Unpublished study prepared by International 

Research & Development Corp. 703 p.

45117902 Hoffman, G. (1999) Chloropicrin: An Inhalation Toxicity Study in the Rat via WholeBody Exposure: Lab Project Number: 99-5387. Unpublished study prepared by 

Huntingdon Life Sciences. 202 p.

47102101 Flatman, D. (2004) Chloropicrin: Acute Toxicity to Daphnia magna. Project Number: 

RDB/019/033845. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 35 p.

47102103 Flatman, D. (2004) Chloropicrin: Acute Toxicity to Fish (Bluegill Sunfish). Project 

Number: RDB/006/033843. Unpublished study prepared by Huntingdon Life Sciences, 

Ltd. 37 p.
Page 39 of 62

MRID Citation

47102102 Flatman, D. (2004) Chloropicrin: Acute Toxicity to Fish (Rainbow Trout). Project 

Number: RDB/005/033842. Unpublished study prepared by Huntingdon Life Sciences, 

Ltd. 34 p.

48442401 Sayers, L. (2010) Chloropicrin - Acute Toxicity to Water Fleas, (Daphnia magna) Under 

Flow-Through Conditions. Project Number: 3140/6112. Unpublished study prepared by 

Springborn Smithers Laboratories. 56 p.

48442402 Sayers, L. (2010) Chloropicrin - Acute Toxicity to Water Fleas, (Daphnia magna) Under 

Flow-Through Conditions. Project Number: 3140/6112. Unpublished study prepared by 

Springborn Smithers Laboratories. 56 p.

48442403 Sayers, L. (2010) Chloropicrin - Acute Toxicity to Mysids (Americamysis bahia) Under 

Flow-Through Conditions. Project Number: 3140/6113. Unpublished study prepared by 

Springborn Smithers Laboratories. 55 p.

48442404 York, D. (2010) Chloropicrin - Acute Toxicity to Eastern Oyster (Crassostrea virginica)

Under Flow-Through Conditions. Project Number: 3140/6114. Unpublished study 

prepared by Springborn Smithers Laboratories. 60 p.

48442405 Sayers, L. (2010) Chloropicrin -Acute Toxicity to Rainbow Trout (Oncorhynchus mykiss) 

Under Flow-Through Conditions. Project Number: 3140/6110. Unpublished study 

prepared by Springborn Smithers Laboratories. 54 p.

48442406 Sayers, L. (2010) Chloropicrin - Acute Toxicity to Bluegill Sunfish (Lepomis 

macrochirus) Under Flow-Through Conditions. Project Number: 3140/6109. Unpublished 

study prepared by Springborn Smithers Laboratories. 56 p.

48442407 Patnaude, M. (2011) Chloropicrin - Acute Contact Toxicity Test with the Honey Bee (Apis 

mellifera). Project Number: 3140/6117. Unpublished study prepared by Springborn

Smithers Laboratories. 36 p.

48442801 Wilby, J. (2009) Chloropicrin: Higher Plant (Lemna) Growth Inhibition Test. Project 

Number: SXC0023. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 39 p.

48442802 Weinberg, J. (2009) Toxicity of Chloropicrin to Six Plant Species: Corn, Soybean, Annual 

Ryegrass, Oilseed Rape, Cucumber & Sunflower: Final Report. Project Number: 

WIL/697004. Unpublished study prepared by WIL Research Laboratories, Inc., Ohio State 

University and Agvise Laboratories, Inc. 527 p.

48442803 Weinberg, J. (2009) A 5-Day Whole-Body Inhalation Toxicity Study of Chloropicrin in 

Northern Bobwhite Quail: Final Report. Project Number: WIL/697002. Unpublished study 

prepared by WIL Research Laboratories, Inc. and Biotechnics, Inc. 563 p.

Antimicrobial Use Studies

00013177 Cooper, P.A. (1973) The Movement of Chloropicrin Vapor in Wood to Control Decay. 

Master's thesis, Oregon State Univ., Dept. of Forest Products. (Unpublished study received 

Apr 23, 1974 under 5316-17; submitted by Namco Chemicals, Inc., San Jose, Calif.; 

CDL:024054-C)

00013189 Cooper, P.A. (1973) The Movement of Chloropicrin Vapor in Wood to Control Decay. 

Master's thesis, Oregon State Univ., Dept. of Forest Products. (Unpublished study received 

Apr 23, 1974 under 5316-17; submitted by Namco Chemicals, Inc., San Jose, Calif.; 

CDL:024054-C)
Page 40 of 62

Appendix A. SIP and STIR Results

SIP

The Screening Imbibition Program (SIP version 1.0; 6/15/2010) was used to calculate an 

upper bound estimate of exposure via drinking water using the solubility of chloropicrin

(1,612 mg/L). The most sensitive acute mammalian toxicity endpoint (rat, LD50 =37.5

mg/kg-bw) for chloropicrin was used. There are no acute or chronic avian dietary 

toxicity data or chronic mammalian dietary toxicity data to use in the model. Drinking 

water exposure to chloropicrin may be a pathway of concern for both avian and 

mammalian species. Results are presented in the tables below. 

SIP Avian Results for Chloropicrin

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 1,306 1,306

Adjusted toxicity value (mg/kg-bw) No data No data

Ratio of exposure to acute toxicity No data No data

Conclusion* Due to insufficient data, risk 

cannot be precluded

Due to insufficient data, risk 

cannot be precluded

SIP Mammalian Results for Chloropicrin

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 277 277

Adjusted toxicity value (mg/kg-bw) 28.8 No data

Ratio of exposure to toxicity 9.61 No data

Conclusion*

Exposure through drinking 

water alone is a potential 

concern for mammals

Due to insufficient data, risk 

cannot be precluded

*Conclusions are for drinking water exposure alone. This does not combine all routes of exposure. 

Therefore, when aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through 

drinking water may contribute to a total exposure that has potential for effects to non-target animals.

STIR

The Screening Tool for Inhalation Risk (STIR version 1.0; 11/23/2010) was used to 

calculate upper bound estimates of chloropicrin exposures via inhalation. The exposure 

pathway assessed is vapor phase inhalation. Droplet inhalation is not applicable because 

there are no spray applications of chloropicrin. Model inputs for chloropicrin included 

molecular weight (164.4 g/mole), vapor pressure (2.38 mmHg), highest application rate 

(350 lb a.i./A) and most sensitive acute oral and inhalation mammalian toxicity endpoints 

(rat, LD50 = 37.5 mg/kg-bw and 4 hr inhalation LC50 0.114 mg/L, respectively). There 

are no acute avian dietary or inhalation toxicity data to use in this model. Vapor 

inhalation was determined to be a potential pathway of concern for avian and mammalian 

species.

STIR Avian (0.020 kg) Results for Chloropicrin

Maximum Vapor Concentration in Air at Saturation (mg/m3) 2.11E+05

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.65E+04

Adjusted Inhalation LD50 (mg/kg) No data
Page 41 of 62

Ratio of Vapor Dose to Adjusted Inhalation LD50 No data Insufficient data

Maximum Post-treatment Spray Inhalation Dose (mg/kg) Not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 Not applicable Not applicable

STIR Mammalian (0.15 kg) Results for Chloropicrin

Maximum Vapor Concentration in Air at Saturation (mg/m3) 2.11+05

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 3.33E+04

Adjusted Inhalation LD50 (mg/kg) 6.79E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 4.90E+03 Proceed to Refinements

Maximum Post-treatment Spray Inhalation Dose (mg/kg) Not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 Not applicable Not applicable
Page 42 of 62

Appendix B. Field Volatility Study Summaries

Direct and Indirect flux determination of Iodomethane and Chloropicrin under

Field Conditions Following Tarped/Raised Bed/ Shallow Shank Injection 

Application of MIDAS 50:50 in Dover, FL (MRID 47295202)

MIDAS 50:50 was applied via a tarped, shank injection to a field measuring 330 feet 

(101 meters) by 330 feet (101 meters) at a rate of 144.8 pounds ai per treated acre in 

January 31, 2007. The field was oriented in a north-south direction. A 0.0013 inch thick 

metalized white tarpaulin (Canslit Inc.) was placed over the application plot. Application 

began at 11:24 am and was completed by 3:01 pm. Eight samplers were placed evenly 

around the field at a distance of 60 feet to measure the amount of MIDAS 50:50 in the air 

around the field. Samplers were placed at a height 5 feet above the ground. 

Additionally, a sample mast was placed in the center of the field and samples collected at 

five different heights. Meteorological measurements were also made onsite. Estimated 

flux rates for the first 5 days are provided in Table 1.

Table 1. Flux Rates Dover, FL Study 

Period Date/Time

Flux Estimation Technique

Indirect Aerodynamic

Flux (μg/m2-s) Reasoning Flux (μg/m2-

s)

Reg.1 Est.2 Est. Reg. Est.

Chloropicrin

1

Day 0 11:00-14:00

11.70 13.57

Slope, no 

intercept 1.24 1.63

2

Day 0 14:00-17:00

6.76 4.65

Slope, no 

intercept 0.30 0.37

3

Day 0 17:00-19:00

6.37 3.25

Slope, no 

intercept 0.22 0.29

4

Day 0 19:00-7:00

0.78 1.09

Slope, no 

intercept 0.64 0.78

5 Day 1 7:00-19:00 1.22 1.35 Slope 0.60 0.67

6

Day 1 19:00-7:00

2.87 1.96

Slope, no 

intercept 0.47 0.55

7 Day 2 7:00-19:00 0.81 0.57 Slope 0.33 0.39

8

Day 2 19:00-7:00

0.27 0.38

Slope, no 

intercept 0.18 0.23

9 Day 3 7:00-19:00 0.35 0.48 Slope 0.10 0.12

10 Day 3 19:00-7:00 0.28 0.33 Slope 0.04 0.06

11 Day 4 7:00-19:00 0.37 0.45 Slope 0.05 0.07

12 Day 4 19:00-7:00 0.19 0.22 Slope 0.05 0.06

1. Reg. – Registrant estimated flux rates.

2. Est. – Versar estimated flux rates.
Page 43 of 62

Direct and Indirect Flux Determination of Iodomethane and Chloropicrin 

under Field Conditions Following Tarped/Raised Bed/Shallow Shank Injection 

Application of MIDAS 50:50 in Bainbridge, GA (MRID 47295203)

MIDAS 50:50 was applied via a tarped, shank injection to a field measuring 330 feet 

(101 meters) by 330 feet (101 meters) at a rate of 154.8 pounds ai per treated acre on 

March 21, 2007. The field was oriented to the northeast. A 0.00125 inch thick tarpaulin, 

Hytiblock 7 black film (Polygrow Inc.) was placed over the application plot. Application 

began at 09:46 am and was completed by 12:46 pm. Eight samplers were placed evenly 

around the field at a distance of 60 feet to measure the amount of MIDAS 50:50 in the air 

around the field. Samplers were placed at a height 5 feet above the ground. 

Additionally, a sample mast was placed in the center of the field and samples collected at 

five different heights. Meteorological measurements were also made onsite. Estimated 

flux rates for the first 5 days are provided in Table 2.

Table 2. Flux Rates Bainbridge, GA Study

Period Date/Time

Flux Estimation Technique

Indirect Aerodynamic

Flux (μg/m2-s) Reasoning Flux (μg/m2-s)

Reg.1 Est.2 Est. Reg. Est.

Chloropicrin

1 Day 0 10:00-14:004 0.422 0.940

Ratio of 

averages 0.054 -0.003

2 Day 0 14:00-17:00 0.323 0.175

Slope, no 

intercept 0.347 0.373

3 Day 0 17:00-20:00 0.322 0.238 Slope 0.370 0.370

4 Day 0 20:00-8:00 0.272 0.292 Slope 0.189 0.190

5 Day 1 8:00-20:00 0.516 0.465

Slope, no 

intercept 0.354 0.354

6 Day 1 20:00-8:00 0.101 0.068 Slope 0.042 0.042

7 Day 2 8:00-20:00 0.096 0.070

Slope, no 

intercept 0.096 0.096

8 Day 2 20:00-8:00 0.022 0.023

Slope, no 

intercept 0.008 0.010

9 Day 3 8:00-20:00 0.030 0.246 Slope 0.018 0.011

10 Day 3 20:00-8:00 0.015 0.012

Slope, no 

intercept 0.002 0.001

11 Day 4 8:00-20:00 0.017 0.020

Slope, no 

intercept 0.008 0.065

12 Day 4 20:00-8:00 0.062 0.077

Ratio of 

averages 0.003 0.002

1. Reg. – Registrant estimated flux rates.

2. Est. – Versar estimated flux rates.

3. All on-site samplers below LOQ.
Page 44 of 62

Direct and Indirect Flux Determination of Iodomethane and Chloropicrin 

under Field Conditions Following Tarped/Raised Bed/Shallow Shank Injection 

Application of MIDAS 50:50 in Hart, MI (MRID 47295204)

MIDAS 50:50 was applied via a tarped, shank injection to a field measuring 330 feet 

(101 meters) by 330 feet (101 meters) at a rate of 159.7 pounds ai per treated acre on 

May 17, 2007. The field was oriented in a north-south direction. A 0.00125 inch thick 

XL Black Blockade (Pliant Corp.) was placed over the application plot. Application 

began at 10:07 am and was completed by 1:14 pm. Eight samplers were placed evenly 

around the field at a distance of 60 feet to measure the amount of MIDAS 50:50 in the air 

around the field. Samplers were placed at a height 5 feet above the ground. 

Additionally, a sample mast was placed in the center of the field and samples collected at 

five different heights. Meteorological measurements were also made onsite. Estimated 

flux rates for the first 3 days for chloropicrin are provided in Table 3.

Table 3. Flux Rates Hart, MI Study

Period Date/Time

Flux Estimation Technique

Indirect Aerodynamic

Flux (μg/m2-s) Reasoning Flux (μg/m2-

s)

Reg.1 Est.2 Est. Reg. Est.

Chloropicrin

1 Day 0 11:00-13:00 0.885 0.96

Slope, no 

intercept 0.117 0.115

2 Day 0 13:00-16:00 0.291 0.12

Slope, no 

intercept 0.03 0.02

3 Day 0 16:00-19:00 NA NA NA NA NA

4 Day 0 19:00-7:00 0.008 0.006 Slope 0.009 0.009

5

Day 1 7:00-19:00

0.022 0.026

Slope, no 

intercept 0.025 0.026

6

Day 1 19:00-7:00

0.025 0.034

Slope, no 

intercept 0.009 0.007

7

Day 2 7:00-19:00

0.009 0.017

Slope, no 

intercept 0.014 0.013

8 Day 2 19:00-7:00 0.017 0.008 Slope 0.002 0.002

1. Reg. – Registrant estimated flux rates.

2. Est. – Versar estimated flux rates.

NA = not assessed. Insufficient data were available to estimate flux rates for these 

periods.

Flux Rate Estimation of Chloropicrin Emissions from a Drip, Buried, NonTarped Application (MRID 47679301)

Chloropicrin was applied via a buried, non-tarped drip irrigation application of 

emulsifiable concentrate of chloropicrin to a field in Yuma AZ. The plot measured 295 

feet north to south and 301 feet east to west with beds 84 inches wide. Tri-Clor EC was 
Page 45 of 62

applied at rate of 297.5 pounds per treated acre in November 2008. Application began 

at 8:00 am on November 3rd and was completed by 16:28. Air samplers were also placed 

on a mast at the center of the field, taking air measurements at 15, 33, 55, 90, 150, and 

180 centimeter heights for aerodynamic flux estimates. Estimated flux rates for the first 

48 hours are provided in Table 4. 

Table 4. Flux Rates Obtained from Yuma, AZ Study 

Period Date/Time

Registrant

Flux (μg/m2-s)

Versar

Flux (μg/m2-s)

1 11/3/2008 08:00 - 13:00 2.660 3.426

2 11/3/2008 13:00 - 19:00 39.300 46.998

3 11/3/2008 19:00 - 01:00 26.800 32.650

4 11/4/2008 01:00 - 07:00 9.720 11.022

5 11/4/2008 07:00 - 13:00 11.800 14.960

6 11/4/2008 13:00 - 19:00 8.150 9.689

7 11/4/2008 19:00 - 01:00 5.730 6.601

8 11/5/2008 01:00 - 07:00 5.530 6.873

9 11/5/2008 07:00 - 18:00 5.590 6.850

10 11/5/2008 18:00 - 07:00 1.360 1.783

11 11/6/2008 07:00 - 18:00 1.390 1.769

12 11/6/2008 18:00 - 07:00 0.537 0.674

13 11/7/2008 07:00 - 18:00 0.407 0.501

14 11/7/2008 18:00 - 07:00 0.119 0.155

15 11/8/2008 07:00 - 18:00 0.181 0.234

16 11/8/2008 18:00 - 07:00 0.040 0.053

17 11/9/2008 07:00 - 18:00 0.000 0.000

18 11/9/2008 18:00 - 07:00 0.019 0.026

19 11/10/2008 07:00 - 18:00 0.000 0.000

20 11/10/2008 18:00 - 07:00 0.006 0.008

21 11/11/2008 07:00 - 18:00 0.046 0.063

22 11/11/2008 18:00 - 07:00 0.009 0.012

23 11/12/2008 07:00 - 18:00 0.000 0.000

24 11/12/2008 18:00 - 07:00 0.009 0.012

25 11/13/2008 07:00 - 18:00 0.000 0.000

26 11/13/2008 18:00 - 07:00 0.006 0.009

27 11/14/2008 07:00 - 18:00 0.000 0.000

28 11/14/2008 18:00 - 07:00 0.000 0.000

29 11/15/2008 07:00 - 18:00 0.000 -0.110

30 11/15/2008 18:00 - 07:00 0.000 0.007

31 11/16/2008 07:00 - 18:00 0.000 -0.097

32 11/16/2008 18:00 - 07:00 0.000 0.005

31 11/16/2008 07:00 - 18:00 2.660 3.426

32 11/16/2008 18:00 - 07:00 39.300 46.998
Page 46 of 62

Field Volatility of 1,3-Dichloropropene and Chloropicrin from Shallow Drip 

Irrigation Application of Telone C-35 (InLine) to Strawberry Beds Covered 

with VIF Tarp (MRID 45112901)

Chloropicrin was applied via drip irrigation to two adjacent raised bed, tarped fields, one 

4.42 acres and one 4.98 acres (7.52 treated acres), in Salinas Valley, CA at a rate of 70.5

pounds ai per acre in October, 1998. Application began at 8:30 AM and was complete at 

12:30 PM. A Hytibar© tarp was placed over the bed tops and sides of the application 

plot, but the inter-bed furrows were not covered. Samplers were placed at a height 1.5 

meters above the ground. Air samplers were also placed on a mast at the center of the 

two fields, taking air measurements at 15, 33, 55, 90, and 150 centimeter heights for 

aerodynamic flux estimates. Flux estimates for the first 48 hours are provided in Table 5.

Table 5. Flux Rates Obtained from Salinas Valley, CA Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 0, Hours 0 - 6 5.63

2 Day 0, Hours 6 - 12 14.85

3 Day 0, Hours 12 - 24 1.15

4 Day 1, Hours 0 - 6 2.05

5 Day 1, Hour 6 - 12 4.37

6 Day 1, Hours 12 - 24 0.16

Field Volatility of 1,3-Dichloropropene and Chloropicrin from Surface Drip 

Irrigation Application of Telone C-35 (InLine) to Vegetable Beds under 

Polyethylene Tarp (MRID 45112902)

Chloropicrin was applied via drip irrigation to a raised bed, tarped field, 10.7 acres (4.33 

treated acres), in Douglas, GA at a rate of 36.4 pounds ai per acre in April, 2000. 

Application began at 12:30 PM and was complete at 5:30 PM. A standard polyethylene 

tarp was placed over the beds of the application plot. Air samplers were also placed on a 

mast at the center of the field, taking air measurements at 15, 33, 55, 90, and 150 

centimeter heights for aerodynamic flux estimates. Wind speed and temperature 

measurements were also made at the center of the field.

Flux estimates for the first 48 hours are provided in Table 6.

Table 6. Flux Rates Obtained from Douglas, GA Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 0, Hours 0 - 5 7.33

2 Day 0, Hours 5 - 19 0.78
Page 47 of 62

Period Day/Hour Flux Rate (ug/m2-s)

3 Day 0, Hours 19 - 24 3.42

4 Day 1, Hours 0 - 5 6.58

5 Day 1, Hours 5 - 19 0.11

6 Day 1, Hours 19 - 24 0.69

Monitoring of Potential Worker Exposure, Field Flux, and Off-Site Air 

Concentration during Chloropicrin Application (MRID 44149201, Plot 1)

Chloropicrin was applied via broadcast to an 8.0 acres, untarped field in Arizona at a rate 

of 170.7 pounds ai per acre in April, 1995. Application began at 7:18 AM and was 

complete at 12:45 PM. Samplers were placed at a height 1.5 meters above the ground. 

Air samplers were also placed on a mast at the center of the field, taking air 

measurements at 15, 33, 55, 90, and 150 centimeter heights for aerodynamic flux 

estimates. Wind speed and temperature measurements were also made at the center of 

the field. Flux estimates for the first 48 hours are provided in Table 7.

Table 7. Flux Rates Obtained from Arizona Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 0, Hours 6 - 11 42.7

2 Day 0, Hours 11 - 17 180.3

3 Day 0, Hours 17 - 23 63.1

4 Day 0, Hour 23 – Day 1, Hour 5 49.6

5 Day 1, Hours 5 - 11 40.0

6 Day 1, Hours 11 - 17 59.9

7 Day 1, Hours 17 - 23 35.0

8 Day 1, Hour 23 – Day 2, Hour 5 18.9

9 Day 2, Hours 5 - 6 9.7

Monitoring of Potential Worker Exposure, Field Flux, and Off-Site Air 

Concentration during Chloropicrin Application (MRID 44149201, Plot 2)

Chloropicrin was applied to a raised bed, untarped field, 2.26 acres in Arizona at a rate of 

85.6 pounds ai per acre in April, 1995. Application began at 10:43 AM and was 

complete at 2:12 PM. Samplers were placed at a height 1.5 meters above the ground. Air 

samplers were also placed on a mast at the center of the field, taking air measurements at 

15, 33, 55, 90, and 150 centimeter heights for aerodynamic flux estimates. Wind speed 
Page 48 of 62

and temperature measurements were also made at the center of the field. Flux estimates 

for the first 48 hours are provided in Table 8.

Table 8. Flux Rates Obtained from Arizona Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 0, Hours 3 – 7 114.1

2 Day 0, Hours 7 – 13 112.8

3 Day 0, Hours 13 – 19 36.0

4 Day 0, Hour 19 – Day 1, Hour 1 22.0

5 Day 1, Hours 1 - 7 9.5

6 Day 1, Hours 7 - 13 8.4

7 Day 1, Hours 13 – 19 6.4

8 Day 1, Hours 19 – 24 3.0

9 Day 1, Hours 24 - 3 1.9

Monitoring of Potential Worker Exposure, Field Flux, and Off-Site Air 

Concentration during Chloropicrin Application (MRID 44149201, Plot3)

Chloropicrin was applied to a raised bed, tarped field, 5.9 acres (3.0 treated acres), in 

Arizona at a rate of 188.7 pounds ai per acre in May, 1995. Application began at 6:25 

AM and was complete at 6:56 PM. A standard tarp was placed over the application plot. 

Samplers were placed at a height 1.5 meters above the ground. Air samplers were also 

placed on a mast at the center of the field, taking air measurements at 15, 33, 55, 90, and 

150 centimeter heights for aerodynamic flux estimates. Wind speed and temperature 

measurements were also made at the center of the field. Flux estimates for the first 48 

hours are provided in Table 9.

Table 9. Flux Rates Obtained from Arizona Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 0, Hours 13 – 18 28.4

2 Day 0, Hours 18 – 24 49.7

3 Day 1, Hours 0 - 6 99.5

4 Day 1, Hours 6 - 12 131.7

5 Day 1, Hours 12 - 18 142.1

6 Day 1, Hours 18 - 24 57.3

7 Day 2, Hour 0 - 6 58.8

8 Day 2, Hours 6 - 12 29.6
Page 49 of 62

9 Day 2, Hours 12 - 13 14.6

Monitoring of Potential Worker Exposure, Field Flux, and Off-Site Air 

Concentration during Chloropicrin Application (MRID 44149201, Plot4)

Chloropicrin was applied via broadcast to an 8.0 acres, tarped field in Arizona at a rate of 

332.1 pounds ai per acre in May, 1995. Application began at 7:13 AM and was complete 

at 11:55 AM. A standard tarp was placed over the application plot. Samplers were 

placed at a height 1.5 meters above the ground. Air samplers were also placed on a mast 

at the center of the field, taking air measurements at 15, 33, 55, 90, and 150 centimeter 

heights for aerodynamic flux estimates. Wind speed and temperature measurements were 

also made at the center of the field.

Flux estimates for the first 48 hours are provided in Table 10.

Table 10. Flux Rates Obtained from Arizona Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 0, Hours 5 - 11 59.2

2 Day 0, Hours 11 - 17 19.6

3 Day 0, Hours 17 - 23 29.5

4 Day 0, Hour 23 – Day 1, Hour 5 211.0

5 Day 1, Hours 5 – 11 172.7

6 Day 1, Hours 11 – 17 30.2

7 Day 1, Hours 17 – 23 28.9

8 Day 1, Hour 23 – Day 2, Hour 5 134.2

Monitoring of Potential Worker Exposure, Field Flux, and Off-Site Air 

Concentration during Chloropicrin Application (MRID 44149201, Plot5)

Chloropicrin was applied via broadcast to an 8.4 acres, tarped field in Yakima, WA at a 

rate of 343 pounds ai per acre in October, 1995. Application began at 7:55 AM and was 

complete at 3:22 PM. A standard tarp was placed over the application plot and punched 

towards the end of Day 5. Samplers were placed at a height 1.5 meters above the ground. 

Air samplers were also placed on a mast at the center of the field, taking air 

measurements at 15, 33, 55, 90, and 150 centimeter heights for aerodynamic flux 

estimates. Wind speed and temperature measurements were also made at the center of 

the field. Flux estimates for the highest 24-hour period while tarped and the highest 24-

hour period after punching of the tarp are provided in Table 11.
Page 50 of 62

Table 11. Flux Rates Obtained from Yakima, WA Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 1, Hour 23 – Day 2, Hour 5 5.7

2 Day 2, Hours 5 – 11 23.3

3 Day 2, Hours 11 – 17 8.3

4 Day 2, Hours 17 – 23 7.5

5 Day 5, Hour 23 - Day 6, Hour 5 35.2

6 Day 6, Hours 5 – 11 70.4

7 Day 6, Hours 11 – 17 10.2

8 Day 6, Hours 17 – 23 19.9

Monitoring of Potential Worker Exposure, Field Flux, and Off-Site Air 

Concentration during Chloropicrin Application (MRID 44149201, Plot6)

Chloropicrin was applied via broadcast to an 8.4 acres, tarped field in Bradenton, FL at a 

rate of 346 pounds ai per acre in January, 1996. Application began at 7:52 AM and was 

complete at 1:22 PM. A standard tarp was placed over the application plot and punched 

at the beginning of Day 6. Samplers were placed at a height 1.5 meters above the ground. 

Air samplers were also placed on a mast at the center of the field, taking air 

measurements at 15, 33, 55, 90, and 150 centimeter heights for aerodynamic flux 

estimates. Wind speed and temperature measurements were also made at the center of 

the field. Flux estimates for the highest 24-hour period while tarped and the highest 24-

hour period after punching of the tarp are provided in Table 12.

Table 12. Flux Rates Obtained from Bradenton, FL Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 1, Hour 23 – Day 2, Hour 4 30.2

2 Day 2, Hours 4 – 10 57.8

3 Day 2, Hours 10 – 16 21.7

4 Day 2, Hours 16 – 23 4.46

5 Day 5, Hour 23 - Day 6, Hour 4 22.0

6 Day 6, Hours 4 – 10 47.8

7 Day 6, Hours 10 – 16 9.7

8 Day 6, Hours 16 – 23 4.4
Page 51 of 62

Chloropicrin Emissions and Offsite Drift from Tarped and Non-tarped 

Fields Treated by Drip Irrigation Application Method (MRID 4745601)

Chloropicrin was applied to two raised bed fields in Yumaz AZ, one tarped and one 

untarped, each approximately 4.4 acres in size and at a rate of 403 pounds ai per treated 

acre in September, 1999. Application on the tarped field began at 7:00 AM and was 

complete at 12:30 PM. Application on the untarped field began at 9:00 AM and was 

complete at 2:30 PM. Samplers were placed at a height 1.5 meters above the ground. Air 

samplers were also placed on a mast at the center of the field, taking air measurements at 

15, 33, 55, 90, and 150 centimeter heights for aerodynamic flux estimates. Wind speed 

and temperature measurements were also made at the center of the field. Flux estimates 

are provided in Table 13.

Table 13. Flux Rates Obtained from Yuma AZ Study

Period Date Time

Flux Rate (ug/m2-s)

Aerodynamic 

Method

Indirect 

Method

Estimated Reported Estimated

Untarped Field

1 9/3/1999 9:00 - 13:00 0.11 0.1 4.06

2 9/3/1999 13:00 - 19:00 19.42 16.00 5.71

3 9/3/1999 19:00 - 6:00 7.69 8.00 14.07

4 9/4/1999 6:00 - 13:00 35.88 46.00 21.52

5 9/4/1999 13:00 - 19:00 41.53 46.00 4.56

6 9/4/1999 19:00 - 7:00 12.31 12.00 9.28

7 9/5/1999 7:00 - 13:00 1.85 2.00 4.14

8 9/5/1999 13:00 - 19:00 7.37 9.00 2.14

9 9/5/1999 19:00 - 6:00 4.35 4.00 1.17

10 9/6/1999 6:00 - 13:00 2.22 3.00 1.63

11 9/6/1999 13:00 - 19:00 1.12 1.00 0.74

12 9/6/1999 19:00 - 6:00 0.21 0.20 0.50

13 9/7/1999 6:00 - 13:00 0.14 0.10 1.84

14 9/7/1999 13:00 - 19:00 0.09 0.06 1.86

15 9/7/1999 19:00 - 7:00 0.32 0.30 4.86

16 9/8/1999 7:00 - 13:00 0.68 0.70 5.28

17 9/8/1999 13:00 - 20:00 0.06 0.07 0.28

18 9/8/1999 20:00 - 7:00 0.34 0.30 1.50

19 9/9/1999 7:00 - 13:00 0.06 0.07 0.63

20 9/9/1999 13:00 - 19:00 0.00 0.00 0.57

Tarped Field

1 9/7/1999 7:00 - 13:00 5.14 5.0 0.32

2 9/7/1999 13:00 - 19:00 15.71 16.0 0.30

3 9/7/1999 19:00 - 6:00 2.49 2.0 3.83

4 9/8/1999 6:00 - 13:00 2.36 2.0 0.60
Page 52 of 62

Period Date Time

Flux Rate (ug/m2-s)

Aerodynamic 

Method

Indirect 

Method

Estimated Reported Estimated

5 9/8/1999 13:00 - 19:00 2.38 2.0 0.44

6 9/8/1999 19:00 - 7:00 0.36 0.4 0.25

7 9/9/1999 7:00 - 13:00 0.42 0.4 0.37

8 9/9/1999 13:00 - 19:00 0.80 0.8 9.41

9 9/9/1999 19:00 - 7:00 0.11 0.1 0.43

10 9/10/1999 7:00 - 13:00 0.22 0.2 0.60

11 9/10/1999 13:00 - 19:00 0.10 0.09 2.55

Monitoring of Chloropicrin Field Emissions from Shank Applications at 

Shallow and Deep Injection depths (MRID 47576901)

Four field studies were conducted in Wasco, CA in May of 2008: one shank injection, 

broadcast tarped application, one shank injection, flatfume tarped application, and two 

shank injection, untarped applications, one at an injection depth of 12 inches and one at 

an injection depth of 18 inches.

For the shank injection, broadcast tarped application, chloropicrin was applied to a one 

acre field at a rate of 358 pounds ai per treated acre. Application began at 7:47 AM and 

was complete at 8:23 AM. A 1-mil polyethylene tarp was placed over the application 

plot and split on Day 6 and removed on Day 7. For the flat fume, tarped application, 

chloropicrin was applied to a one acre field at a rate of 320 pounds ai per treated acre. 

Application began at 9:41 AM and was complete at 9:55 AM. A 1-mil polyethylene tarp 

was placed over the application plot and split on Day 6 and removed on Day 7. For the 

shank injected, untarped application conducted at 12 inches, chloropicrin was applied to a 

one acre field at a rate of 197 pounds ai per treated acre. Application began at 11:10 AM 

and was complete at 11:35 AM. For the shank injected, untarped application conducted 

at 18 inches, chloropicrin was applied to a one acre field at a rate of 321 pounds ai per 

treated acre. Application began at 12:18 PM and was complete at 1:00 PM. 

Samplers were placed at a height 1.5 meters above the ground. Air samplers were also 

placed on a mast at the center of the field, taking air measurements at 1, 2, 3, 6, and 10 

feet heights for integrated horizontal flux estimates. Due to difficulties collecting the 

concentration samples at 10 feet, these samples were not used in the flux estimation. 

Wind speed and wind direction measurements were made at the center of the field. Flux 

estimates for all four sites are provided in Table 14.
Page 53 of 62

Table 14. Flux Rates Obtained from Wasco, CA Study

Period

Field 1 Field 2 Field 3 Field 4

Broadcast

Tarped

Flat Fume

Tarped

Broadcast, Untarped, 

12"

Broadcast, Untarped, 

18"

Estimated Reported Estimated Reported Estimated Reported Estimated Reported

05/28/2008, ST -

14:00* 7.18 5.66 8.4 9.96 10.1 14.5 24.0 37.07

05/28/2008, 14:00 -

19:30 12.8 14.7 13.6 15.6 11.0 9.8 7.0 8.0

05/28/2008, 19:30 -

1:30 11.5 12.1 15.4 16.0 17.1 17.9 32.4 33.9

05/29/2008, 1:30 -

7:30 21.5 7.46 9.8 14.1 25.2 4.8 55.8 64.1

05/29/2008, 7:30 -

13:30 55.3 57.6 36.6 38.1 23.6 24.6 26.7 27.8

05/29/2008, 13:30 -

19:30 72.7 75.1 34.9 35.9 30.0 30.9 34.6 35.6

05/29/2008, 19:30 -

1:30 22.8 28.6 19.0 20.0 57.0 60.5 59.9 74.8

05/30/2008, 1:30 -

7:30 14.2 14.9 10.6 11.1 34.2 35.7 49.4 51.6

05/30/2008, 7:30 -

19:30 56.6 61.6 19.9 21.7 16.2 17.7 23.7 25.9

05/30/2008, 19:30 -

7:30 22.3 25.0 16.7 18.7 35.5 39.9 42.9 56.2

05/31/2008, 7:30 -

19:30 34.9 38.8 12.3 13.7 10.0 11.2 14.1 15.7

* ST = start time. ST = 07:26 for Field 1, 09:30 for Field 2, 10:55 for Field 3, and 12:15 for Field 4.
Page 54 of 62

Monitoring of Chloropicrin Emissions from Field and Greenhouse Drip 

Irrigation Applications, and Implied Worker Inhalation Exposure from 

Applications of Chloropicrin by Shank Injection, Drip Irrigation Systems 

and at Tree Replant Sites (MRID 46420201) – Site 16

Chloropicrin was applied via drip irrigation to a raised bed, tarped field, 8.7 acres (4.5 

treated acres), in Salinas, CA at a rate of 155.7 pounds ai per acre in August, 2003. 

Application began at 7:30 AM and was complete at 11:15 AM. A standard polyethylene 

tarp was placed over the application plot. Reentry tarp punching was conducted 10 days 

after application. Samplers were placed at a height 1.5 meters above the ground. Air 

samplers were also placed on a mast at the center of the field, taking air measurements at 

15, 33, 55, 90, and 150 centimeter heights for aerodynamic flux estimates. Wind speed 

and temperature measurements were also made at the center of the field. Flux estimates 

for the first 48 hours are provided in Table 15.

Table 15. Flux Rates Obtained from Salinas, CA Study

Period Day/Hour Flux Rate (ug/m2-s)

1 Day 0, Hours 0 – 4 27.0

2 Day 0, Hours 4 – 8 70.1

3 Day 0, Hours 8 – 12 23.3

4 Day 0, Hours 12 - 16 5.7

5 Day 0, Hours 16 – 20 4.8

6 Day 0, Hours 20 – 24 2.6

7 Day 1, Hours 0 – 4 7.3

8 Day 1, Hours 4 – 8 11.7

9 Day 1, Hours 8 – 12 5.7

10 Day 1, Hours 12 - 16 2.2

11 Day 1, Hours 16 – 20 0.9

12 Day 1, Hours 20 – 24 0.9

Direct Flux Determination of Chloropicrin Emissions from Shank, Bedded, 

Non-Tarped Applications (MRID 48033801)

Pic Plus (85.5% chloropicrin) was applied at a target rate of 175 lb /ac to a 3-acre field in 

Elkton, FL in December 3, 2009. Air monitoring was accomplished using sorbent tubes 

and SKC® personal air sampling pumps. Flux monitoring was conducted with a single 

mast cantrally located in the plot. The mast was constructed to sample the air at sic 

heights: 15, 33, 55, 90, 150 and 180 cm. Flux estimates for the first 27 hours are provided 

in Table 16.
Page 55 of 62

Table 16. Flux Rates Obtained from Elkton, FL Study

Period Duration (hr) Time (middle of period) Flux Rate (ug/m2-s)

1 2.6 12/3/09 17:43 5.556

2 6 12/3/09 22:00 0.593

3 6 12/4/09 4:00 0.423

4 6 12/4/09 10:00 0.706

5 6 12/4/09 16:00 0.198

Monitoring 1,3-Dichloropropene, Chloropicrin and Methyl Isothiocyanate 

Emissions from Shank Applications at Three Sites Near Duette, Florida 

(MRID 47813901)

A comparative emissions data were generated from three different shank application 

scenarios in a bed-plastic mulch vegetable production system. All three tests were 

conducted in close proximity and on the same date with concurrent air and soil 

monitoring to ensure meteorological and soil conditions. The flux rates were computed 

using the integrated horizontal flux method (IHF). Each test field plot was approximately 

one acre in size. The chloropicrin application was approximately 170 lb/acre.

Profile samples were collected on sampling masts places at the approximate center of 

each plot of the test fields shortly after passage of the application rig. Air sample tubes 

were placed along the vertical profiles on each filed at 1, 3, 6, and 10 ft above each field 

during each period of the study. Flux estimates for the three fields are provided in Table 

17.

Table 17. Flux Rates Obtained from Duette, FL Study

Sample Interval 

Times

Field 1 Field 2 Field 3

Metalized Film Virtually Impermeable 

Film

Metalized Film

(ug/m2-s) (ug/m2-s) (ug/m2-s)

Estimated Reported Estimated Reported Estimated Reported

1/14/2009 9:30 -

15:30 17.05 18.67 1.77 2.24929 9.55 4.53704

1/14/2009 15:30 

- 21:30 0.89219 0.00253 1.2612394 0.00259 0.003 0.00301

1/14/2009 21:30 

- 3:30 6.57361 0.00261 5.3571934 0.00242 0.80874001 0.00285

1/15/2009 3:30 -

9:30 6.42487 0.00254 6.4067525 0.00275 1.20635673 0.00271

1/15/2009 9:30 -

15:30 16.586 0.0028 13.521113 0.00244 2.66537817 0.00296

1/15/2009 15:30 

- 21:30 7.57669 0.00274 6.4205641 0.00284 1.33503861 0.0029

1/15/2009 21:30 1.80171 0.00276 1.374688 0.00222 1.81810091 0.00301
Page 56 of 62

- 3:30

1/16/2009 3:30 -

13:30 2.60878 0.00274 16.14767 0.00262 3.22137123 0.00286

1/16/2009 13:30 

- 1:30 7.20999 0.00261 0.9469805 0.00298 1.00569172 0.00285

1/17/2009 1:30 -

13:30 0.34477 0.26673 1.8243464 0.00299 0.27904869 0.00265

1/17/2009 13:30 

- 1:30 0.14543 0.2659 0.1649281 0.00302 0.15136294 0.00243

1/18/2009 1:30 -

13:30 0.32508 0.22141 0.111022 0.0737 0.09852181 0.00256

1/18/2009 13:30 

- 1:30 0.53899 0.38129 0.2740392 0.00297 0.30782014 0.00259

1/19/2009 1:30 -

13:30 0.39167 0.31492 1.3308907 0.00279 0.23839527 0.00277

1/19/2009 13:30 

- 1:30 0.82339 0.60557 0.8049912 0.56659 0.43581863 0.00283

1/20/2009 1:30 -

13:30 1.10735 0.91726 1.2934923 0.96547 3.12117462 0.00269

1/20/2009 13:30 

- 1:30 0.37205 0.46641 0.3920304 0.53091 0.47268152 0.00248

1/21/2009 1:30 -

13:30 0.29 0.00262 0.2880564 0.00269 0.27600537 0.00302

1/21/2009 13:30 

- 1:30 0.16612 0.00251 0.1639747 0.00269 0.16809599 0.00262

1/22/2009 1:30 -

13:30 0.08596 0.0025 0.0872234 0.00279 0.08314276 0.0026

1/22/2009 13:30 

- 1:30 0.0737 0.00247 0.0678296 0.00279 0.07184505 0.00275

1/23/2009 1:30 -

13:30 0.06781 0.00259 0.067549 0.0027 -0.0006807 0.0027

Monitoring Methyl Bromide and Chloropicrin Field Emissions from Shank 

Applications at Shallow and Deep Injection Depths (MRID 48006001)

The targeted application rates of 180 lb/ac were made to five 1-acre field located near 

Wasco, CA on June 2, 2009. Air sampling was conducted starting with the beginning of 

each application and continued through June 15, 2009. The five test scenarios are as 

follows: (1) a shallow, broadcast, tarped application with 12” injection depth and 

polyethylene tarp sealing, (2) a shallow, broadcast, tarped application with 12” injection 

depth and EVOH resin barrier tarp sealing, (3) a shallow, broadcast, tarped application 

with 12” injection depth and polyethylene tarp + potassium thiosulfate sealing, (4) a 

deep, strip, tarped application with 18” injection depth and EVOH resin barrier tarp 

sealing, and (5) a deep, broadcast, tarped application with 18” injection depth and EVOH 

resin barrier tarp sealing. Flux estimates for the five fields are provided in Table 18.
Page 57 of 62

Table 18. Flux Rates Obtained from Wasco, CA Study

Estimated flux (μg/m2-sec)

Duration Field1 Field2 Field3 Field4 Field5

06/02/2009 09:00 - 13:00 17.41 25.82 30.97 5.19 1.78

06/02/2009 13:00 - 19:00 31.03 6.97 7.2 5.19 1.78

06/02/2009 19:00 - 01:00 15.54 2.08 1.86 1.69 2.1

06/03/2009 01:00 - 07:00 17.48 0.89 0.91 0.86 0.91

06/03/2009 07:00 - 13:00 11.39 1.19 1.22 4.62 4.04

06/03/2009 13:00 - 19:00 23.97 5.32 5.95 6.33 5.47

06/03/2009 19:00 - 01:00 6.46 8.53 6 3.87 6.31

06/04/2009 01:00 - 07:00 1.3 1.97 1.76 2.52 5.9

06/04/2009 07:00 - 19:00 4.22 1.26 1.18 4.28 1.15

06/05/2009 19:00 - 07:00 1.14 1.74 1.61 1.7 1.58

06/05/2009 07:00 - 19:00 0.94 0.25 1.28 1.39 1.24

06/06/2009 19:00 - 07:00 0.86 1.36 0.89 0.95 0.88

06/06/2009 07:00 - 19:00 1.5 1.64 1.46 1.54 1.4

06/07/2009 19:00 - 07:00 0.41 0.77 0.72 0.6 0.58

06/07/2009 07:00 - 19:00 0.68 1.43 1.29 1.3 1.24

06/08/2009 19:00 - 07:00 0.59 1.66 0.84 0.63 0.62

06/08/2009 07:00 - 13:00 0.05 3.86 0.85 0.8 2.25

06/08/2009 13:00 - 19:00 1.45 2.82 1.4 4.76 5.93

06/08/2009 19:00 - 01:00 0.1 1.31 1.2 4.6 3.47

06/09/2009 01:00 - 07:00 1.52 1.53 1.56 1.5 2.65

06/09/2009 07:00 - 19:00 1.65 1.57 1.6 2.03 2.46

06/10/2009 19:00 - 07:00 1.2 1.52 1.23 0.65 1.62

06/10/2009 07:00 - 19:00 1.79 3.08 1.79 1.81 0.57

06/11/2009 19:00 - 07:00 1.85 0.93 1.19 0.93 1.26

06/11/2009 07:00 - 19:00 1.3 0.88 0.99 1.54 1.45

06/12/2009 19:00 - 07:00 0.74 0.83 0.79 0.73 1.01

06/12/2009 07:00 - 19:00 1.49 1.64 1.5 1.44 1.38

06/13/2009 19:00 - 07:00 1.3 1.36 1.35 0.93 1.37

06/13/2009 07:00 - 19:00 1.58 1.69 1.61 1.93 1.49

06/14/2009 19:00 - 07:00 0.96 1.05 0.98 1.09 0.95

06/14/2009 07:00 - 19:00 1.54 1.61 1.47 1.74 1.42

06/15/2009 19:00 - 07:00 0.72 0.79 0.64 0.73 0.66
Page 58 of 62

Monitoring of Methyl Bromide and Chloropicrin Field Emissions from 

Shank (Bedded and Broadcast) and a Methyl Bromide Hot-Gas Application 

under Totally Impermeable Film (MRID 48107601)

The objective was to generate comparative emissions dada from three application 

methods for methyl bromide and chloropicrin at practical application rates for each 

method. Among the three, only one test generates useful chloropicrin emission data. 

The test is for in-bed shank application under TIF (totally impermeable tarp). This 

application was conducted January 15 on a vegetable farm just north of Ft. Pierce, FL. 

The applied are was 0.59 acres. The targeted rate is 235 lb/ac chloropicrin. Flux 

estimates are provided in Table 19.

Table 19. Flux Rates Obtained from Fort Pierce, FL Study

Period 

No. Sample Interval Times Start Time Duration Reported Flux

(ug/m2-s)

1 1/15/2010 9:45 - 13:00 1/15/10 9:45 3:15 14.1

2 1/15/2010 13:00 - 19:00 1/15/10 13:00 6:00 0.11

3 1/15/2010 19:00 - 01:00 1/15/10 19:00 6:00 0.05

4 1/16/2010 01:00 - 07:00 1/16/10 1:00 6:00 0.66

5 1/16/2010 07:00 - 13:00 1/16/10 7:00 6:00 0.13

6 1/16/2010 13:00 - 19:00 1/16/10 13:00 6:00 0.17

7 1/16/2010 19:00 - 01:00 1/16/10 19:00 6:00 0.15

8 1/17/2010 01:00 - 07:00 1/17/10 1:00 6:00 4.72

9 1/17/2010 07:00 - 19:00 1/17/10 7:00 12:00 0.39

10 1/17/2010 19:00 - 07:00 1/17/10 19:00 12:00 0.07

11 1/18/2010 07:00 - 19:00 1/18/10 7:00 12:00 0.05

12 1/18/2010 19:00 - 07:00 1/18/10 19:00 12:00 0.01

13 1/19/2010 07:00 - 19:00 1/19/10 7:00 12:00 0.17

14 1/19/2010 19:00 - 07:00 1/19/10 19:00 12:00 0.02

15 1/20/2010 07:00 - 19:00 1/20/10 7:00 12:00 0.29

16 1/20/2010 19:00 - 07:00 1/20/10 19:00 12:00 0.11

17 1/21/2010 07:00 - 19:00 1/21/10 7:00 12:00 1.34

18 1/21/2010 19:00 - 07:00 1/21/10 19:00 12:00 0.05

19 1/22/2010 07:00 - 19:00 1/22/10 7:00 12:00 0.05

20 1/22/2010 19:00 - 07:00 1/22/10 19:00 12:00 0.02

21 1/23/2010 07:00 - 19:00 1/23/10 7:00 12:00 0.29

22 1/23/2010 19:00 - 07:00 1/23/10 19:00 12:00 0.04

23 1/24/2010 07:00 - 20:00 1/24/10 7:00 13:00 0.12

24 1/24/2010 20:00 - 07:45 1/24/10 20:00 11:45 0.08
Page 59 of 62

Monitoring 1,3-Dicholoropropene and Chloropicrin Emissions from SolidTarp Shank Injections at Two Sites Near Fort Pierce, Florida (MRID 

48085701)

The objective was to generate comparative emissions dada from two different shank 

application scenarios (standard shank injection versus low distributed shank injection) in 

a Florida vegetable production system. Air concentrations were monitored over a 10-dayperiod using solid sorbent air sampling tubes. The flux rates were computed using the 

integrated horizontal flux method (IHF) based on measured air concentrations along the 

vertical profile (from 0.3 to 2.4 m). For field 1, prior to application, the soil surface was 

sealed with a single drum smooth roller. The fumigant was applied with a low 

disturbance application rig at 8” depth. The soil was immediately covered with smooth, 

1.0 mil, high density polyethylene (HDPE) plastic. For field 2, prior to application, soil 

tillage was performed using a field cultivator with rolling basket attachments. The 

fumigant was applied using swept back shanks at 8” depth. The soil was also 

immediately covered with HDPE plastic. Flux estimates are provided in Table 20.

Table 20. Flux Rates Obtained from Fort Pierce, FL Study

Period 

No.

Field 1 Field 2

Sample Interval Times

Reported 

Flux

(ug/m2-s)

Sample Interval Times

Reported 

Flux

(ug/m2-s)

1 11/17/2009 8:30 - 18:30 19.89 11/17/2009 8:00 - 12:00 4.23

2 11/17/2009 18:30 - 18:30 19.89 11/17/2009 12:00 - 19:00 32.48

3 11/17/2009 18:30 -

11/18/2009 0.30 24.21

11/17/2009 19:00 -

11/18/2009 1:00 27.35

4 11/18/2009 0:30 - 6:30 14.47 11/18/2009 1:00 - 7:00 28.42

5 11/18/2009 6:30 - 12:30 42.07 11/18/2009 7:00 - 13:00 25.64

6 11/18/2009 12:30 - 18:30 46.83 11/18/2009 1:00 - 19:00 46.49

7 11/18/2009 18:30 -

11/19/2009 0:30 15.17

11/18/2009 19:00 -

11/19/2009 1:00 21.95

8 11/19/2009 0:30 - 6:30 11.34 11/19/2009 1:00 - 7:00 16.40

9 11/19/2009 6:30 -18:30 32.51 11/19/2009 7:00 - 19:00 39.03

10 11/19/2009 18:30 -

11/20/2009 6:30 8.24

11/19/2009 19:00 -

11/20/2009 7:00 14.52

11 11/20/2009 6:30 - 18:30 17.54 11/20/2009 7:00 - 19:00 17.86

12 11/20/2009 18:30 -

11/21/2009 6:30 4.91

11/20/2009 19:00 -

11/21/2009 7:00 7.66

13 11/21/2009 6:30 - 18:30 14.07 11/21/2009 7:00 - 19:00 15.51

14 11/21/2009 18:30 -

11/22/2009 6:30 7.79

11/21/2009 19:00 -

11/22/2009 7:00 7.80

15 11/22/2009 6:30 - 18:30 10.88 11/22/2009 7:00 - 19:00 9.44

16 11/22/2009 18:30 -

11/23/2009 6:30 8.64

11/22/2009 19:00 -

11/23/2009 7:00 7.21
Page 60 of 62

17 11/23/2009 6:30 - 18:30 11.15 11/23/2009 7:00 - 19:00 12.29

18 11/23/2009 18:30 -

11/24/2009 6:30 4.78

11/23/2009 19:00 -

11/24/2009 7:00 4.33

19 11/24/2009 6:30 - 18:30 7.48 11/24/2009 7:00 - 19:00 6.90

20 11/24/2009 18:30 -

11/25/2009 6:30 4.02

11/24/2009 19:00 -

11/25/2009 7:00 3.65

21 11/25/2009 6:30 - 18:30 3.85 11/25/2009 7:00 - 19:00 4.82

22 11/25/2009 18:30 -

11/26/2009 6:30 3.13

11/25/2009 19:00 -

11/26/2009 7:00 2.73

23 11/26/2009 6:30 - 18:30 3.02 11/26/2009 7:00 - 19:00 6.57

24 11/26/2009 18:30 -

11/27/2009 6:30 0.99

11/26/2009 19:00 -

11/27/2009 7:00 1.19

Chloropicrin Flux Rates for Drip Fumigation with PE and TIF Tarps, Water 

Seal and KTS at Salinas, California in September 2007 (MRID 48087401)

The objective was to generate comparative emissions dada from four drip applications of 

chloropicrin, with all field located in close proximity to each other, and with air 

monitoring conducted concurrently to ensure that meteorological and soil conditions were 

similar at all four sites. The design differences among each field are the sealing methods. 

Field #1 was tarped with standard LDPE, and no water seal and without potassium 

thiosulfate addition. Field #2 was tarped with TIF, and no water seal and without 

potassium thiosulfate addition. Field #3 was tarped with standard LDPE, and with water 

seal and with potassium thiosulfate addition. Field #4 was tarped with standard LDPE, 

and with water seal and without potassium thiosulfate addition.

The flux estimates are presented in Table 21 to Table 24.

Table 21. Flux Rates Obtained Field #1 from Salinas, CA Study

Period Sample Interval Times Est. Flux Reported Flux

No. (ug/m2-s) (ug/m2-s)

1 9/27/2007 08:00-12:45 72.48 70.62

2 9/27/2007 12:45-18:30 108.74586 77.732

3 9/27/2007 18:30-00:45 17.69839 17.73

4 9/28/2007 00:45-06:30 6.8765511 10.09

5 9/28/2007 06:30-12:30 17.475552 14.61

6 9/28/2007 12:30-18:30 10.896526 8.51

7 9/28/2007 18:30-00:30 4.5526754 4.18

8 9/29/2007 00:30-06:30 2.0175433 1.88

9 9/29/2007 06:30-18:30 1.2132923 1.03

10 9/29/2007 18:30-06:30 1.9034823 1.71

11 9/30/2007 06:30-18:30 0.9475694 0.78

12 9/30/2007 18:30-06:30 0.669106 0.39

13 10/1/2007 06:30-18:30 0.4130348 0.33
Page 61 of 62

14 10/1/2007 18:30-06:30 0.2196138 0.5

Table 22. Flux Rates Obtained Field #2 from Salinas, CA Study

Period 

No. Sample Interval Times Est. Flux Reported Flux

(ug/m2-s) (ug/m2-s)

1 9/27/2007 08:00-13:00 12.18 3.96

2 9/27/2007 13:00-19:00 9.9188583 5.38

3 9/27/2007 19:00-01:00 5.0246402 2.48

4 9/28/2007 01:00-06:45 2.0274643 1.39

5 9/28/2007 06:45-12:45 5.4529102 2.15

6 9/28/2007 12:45-18:45 3.7133395 0.5

7 9/28/2007 18:45-01:00 0.1244568 0.5

8 9/29/2007 01:00-07:00 0.0280541 0.1

9 9/29/2007 07:00-19:00 1.0429712 0.5

10 9/29/2007 19:00-07:00 0.3752138 0.1

11 9/30/2007 07:00-19:00 0.0710577 0.5

12 9/30/2007 19:00-07:00 0.1493052 0.1

13 10/1/2007 07:00-19:00 0.3027861 0.1

14 10/1/2007 19:00-07:00 0.0083464 0.1

Table 23. Flux Rates Obtained Field #3 from Salinas, CA Study

Period 

No. Sample Interval Times Est. Flux Reported Flux

(ug/m2-s) (ug/m2-s)

1 9/27/2007 08:00-13:15 15.66 19.15

2 9/27/2007 13:15-19:15 74.324839 10.82

3 9/27/2007 19:15-01:15 39.377305 7.1

4 9/28/2007 01:15-07:15 21.792712 8.82

5 9/28/2007 07:15-13:00 35.161154 5.68

6 9/28/2007 13:00-19:00 46.471985 4.9

7 9/28/2007 19:00-01:15 20.070334 3.69

8 9/29/2007 01:15-07:15 13.31243 3.04

9 9/29/2007 07:15-19:15 12.751401 1.56

10 9/29/2007 19:15-07:15 11.860213 1.79

11 9/30/2007 07:15-19:15 3.3435154 2.03

12 9/30/2007 19:15-07:15 1.1267063 0.85

13 10/1/2007 07:15-19:15 3.3279015 0.5

14 10/1/2007 19:15-07:00 0.8679198 0.49
Page 62 of 62

Table 24. Flux Rates Obtained Field #4 from Salinas, CA Study

Period 

No. Sample Interval Times Est. Flux Reported Flux

(ug/m2-s) (ug/m2-s)

1 9/27/2007 08:00-13:30 65.69 50.44

2 9/27/2007 13:30-19:30 103.7689 29.53

3 9/27/2007 19:30-01:30 48.388789 13.76

4 9/28/2007 01:30-07:30 22.938605 9.78

5 9/28/2007 07:30-13:15 43.511546 7.04

6 9/28/2007 13:15-19:30 19.707023 5.19

7 9/28/2007 19:30-01:30 16.994678 3.32

8 9/29/2007 01:30-07:30 12.379164 2.25

9 9/29/2007 07:30-19:30 8.5184615 1.46

10 9/29/2007 19:30-07:30 8.4661379 0.92

11 9/30/2007 07:300-19:30 2.7015752 0.5

12 9/30/2007 19:30-07:30 0.5635278 0.23

13 10/1/2007 07:30-19:45 0.6853856 0.5

14 10/1/2007 19:45-07:30 0.6893363 0.5